A PROCESS FOR BLEACHING WEBS OR YARNS OF VEGETABLE TEXTILE MATERIALS
Year: 1885

page_text: "
I, WILLIAM MATHER of Salford in the county of Lancaster Engineer, do hereby
declare the nature of my invention for A PROCESS FOR BLEACHING WEBS OR
YARNS OF VEGETABLE TEXTILE MATERIALS and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:-
In the Provisional Specification filed by me on the 25th April 1881 No 1778, and
in the specification to Letters Patent dated 28th May 1883 N° 2641, there is
described an operation of steaming fabrics or yarns of vegetable fibre for facilitating
the bleaching thereof. Again, in the Specification to Thompson's Patent, dated the
3rd February 1883, No 595, there is described an operation for facilitating the
bleaching of vegetable textile materials by saturating them with bleaching liquor
and exposing them to the action of carbonic acid gas. Also in the Specification to
Cross' Patent dated 30 Nov 1880 N° 4984 there is described as part of a bleaching
process, the treatment of the material with hot water or steam in contact with
sulphites and alkaline solutions. It has been found that although the steaming
operation is in many cases of advantage as an aid to other bleaching operations, and
although good bleaching effects can be obtained by applying that part of the
"Thompson" process, which consists in impregnating the materials with bleaching
liquor and subjecting them to the action of Carbonic acid, neither of these opera-
tions by itself, or in conjunction with other operations commonly employed-such
as boiling in kiers, souring, washing and squeezing, preparatory to the Thompson
Process, or such as the usual treatment with chemicals, souring, washing and
squeezing repeatedly after steaming when steaming is substituted by boiling in
kiers-is successful in giving that character of whiteness which is desired in
bleached materials. Now, my invention consists in applying the two operations
above referred to in combination as successive steps of a process, preferably con-
tinuous, by which bleaching is very rapidly effected, and a high quality of whiteness
is produced. For this purpose, assuming that a continuous web of cotton, linen or
other vegetable material is to be bleached, I pass it continuously in its open form,
exposing its full width, through a series of compartments of apparatus in which it
undergoes the following successive operations, or others equivalent thereto.
Firstly, It is saturated. with or without a preparatory washing in the grey state
with alkaline or other equivalent solution, such as caustic soda or sulphite of
soda or both these substances as described in the Specification No. 4984 above
referred to.
Secondly It is exposed to steam in what is known as a continuous steamer.
Thirdly: It is washed.
Fourthly: It is passed through a solution of sulphuric or muriatic acid or their
equivalents.
Fifthly: It is washed.
To in antunted with chlorine bleaching liquor

page_text: Seventhly: It is subjected to the action of an atmosphere of carbonic acid gas.
Eighthly: It is washed.
Ninthly: It is passed through sulphuric acid solution or its equivalent.
Tenthly: It is again washed and squeezed and finally it is dried.
As in most of these operations it is necessary to provide for some time of
exposure, especially to the steam and to the carbonic acid gas, the web in passing
through compartments where it is thus acted upon, is made to travel over and
under a number of guide rollers, so that it has to pass many times up and down or
to and fro', within the compartments; or it may be suspended in a steaming
chamber, and caused to travel through the steam by means of an endless chain, or
creeper, so as to be exposed to the steam for the requisite number of hours. Again,
it is sometimes necessary to provide for repetition of some of the operations, and
this can be readily effected by duplicating or increasing the number of some of the
compartments of the continuously arranged apparatus. Thus the series consisting
of the steaming, chlorinising, and carbonic acid gas compartments, along with those
for souring washing, and squeezing may be repeated twice or a greater number of
times in close succession. Lines of yarn may be operated on continuously as
described, and, instead of passing a single web of fabric in its spread out form
through the apparatus, several webs in rope form may be passed through it simul-
taneously, at a slower rate, so as to give time for the several agents to penetrate
their folds.
Also the steaming, instead of being continuous with, the rest of the process, as
above described, may be effected by placing the whole web in a closed kier or
vessel and exposing it to the action of steam under pressure for the requisite time,
after which it can be passed continuously through the succeeding compartments.
The construction of the bleaching apparatus and its successive compartments
being of a kind well known, it is unnecessary to describe it. I may however refer
to the Specification of Letters Patent granted to me on the 19th May 1884 N° 7909
as describing an arrangement of bleaching apparatus for operating continuously,
but without the steaming preliminary to the chlorinising and exposure to
carbonic acid gas. Apparatus such as is described in that Specification with a con-
tinuous steaming chamber arranged in front of the washing and chlorinising
compartments, or with a kier or closed vessel suited for steaming under pressure,
would suffice for completely operating as I have described. Most of the machines
and kiers now ordinarily used in bleaching works can be readily adapted for
effecting some of the operations set forth, without materially altering their con-
struction or arrangement.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I hereby declare that I make
no claim to any one of the bleaching operations above mentioned by itself, such as
the steaming with or without sulphites, the chlorinising or the carbonic acid treat-
ment, nor do I claim the chlorinising and carbonic acid treatment taken together
or in conjunction with the washing squeezing and drying, but what I claim is
In bleaching by a continuous process webs or yarns of vegetable textile material,
the combination of the operations of saturating with alkaline or equivalent
solutions, steaming, saturating with bleaching liquor and exposing to the action of
carbonic acid gas, as and for the purpose herein set forth.