AN IMPROVEMENT IN THE PROCESS OF CLEANSING WOOLLEN CLOTHS PREPARATORY TO THE DYEING OF THE SAME
Year: 1876

page_text: LETTERS PATENT to James Henry Rogers, of Bowbridge, Stroud, in the
County of Gloucester, Dyer, for the Invention of "AN IMPROVEMENT IN THE
PROCESS OF CLEANSING WOOLLEN CLOTHS PREPARATORY TO THE DYEING OF
THE SAME."
ealed the 5th January 1877, and dated the 1st November 1876.
PROVISIONAL SPECIFICATION left by the said James Henry Rogers at the
Office of the Commissioners of Patents on the 1st November 1876.
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JAMES HENRY ROGERS, of Bowbridge, Stroud, in the County of Gloucester,
Dyer. AN IMPROVEMENT IN THE PROCESS OF CLEANSING WOOLLEN CLOTHS
PREPARATORY TO THE DYEING OF THE SAME.
"
This Invention relates to an improvement in the process of preparing woollen
cloths for dyeing, the object being to effect an economy in the cost of the acid bath
employed, to produce a better result, and to render the operation less injurious to
the workmen employed.
Hitherto it has been common (owing to the cost of pure hydrochloric acid) to use
the acid obtained as a bye product in the alkali manufacture, but this acid besides
being obtained in a very dilute state (necessitating the use of a large number of
carboys) contained iron in sufficient quantity to color the goods submitted to the
acid bath to an extent that was very objectionable when light colors were required.
Moreover the bath prepared by the use of this acid gave off sulphurous acid fumes,
which caused great inconvenience to the workmen employed. Now in order to remedy
these inconveniences I prepare an hydrochloric acid bath in which the goods are to
be washed or cleansed, by combining sulphuric acid with brine or its equivalent in
a tank of water. The action of the sulphuric acid upon the brine will result in the
formation of hydrochloric acid (which will acidulate the water), and in a deposit of
sulphate of soda on the bottom and sides of the tank, which substance may be
recovered and sold in the market.
The cloth is to be submitted to this bath and worked in the usual way to cleanse
it from the lime or other soaps and other extraneous matters contained in the cloth,
after which it is drained or squeezed to express the liquor therefrom, and rinsed in
the usual way to remove all traces of the acid.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said James Henry Rogers in the Great Seal Patent Office on the 1st May 1877.
JAMES HENRY ROGERS, of Bowbridge, Stroud, in the County of Gloucester,
Dyer. "AN IMPROVEMENT IN THE PROCESS OF CLEANSING WOOLLEN CLOTHS
PREPARATORY TO THE DYEING OF THE SAME."
This Invention relates to an improvement in the process of preparing woollen
cloths for dyeing and finishing, the object being to effect an economy in the cost of
the acid bath employed, to produce a better result, and to render the operation less
injurious to the health of the workmen employed.
Hitherto it has been common (owing to the cost of pure hydrochloric acid) to use,
for the formation of the acid bath, the acid produced as a bi-product in the alkali
manufacture, but this acid, besides being obtained in a very dilute state (necessitating
the use of a large number of carboys) contains iron in sufficient quantity to colour
the goods submitted to the acid bath to. an extent that is very objectionable when
light colours are required. Moreover the bath prepared by the use of this acid gives
off sulphurous acid fumes, which cause great inconvenience to the workmen
employed. Now in order to remedy these inconveniences I prepare a hydrochloric
acid bath in which the goods are to be washed or cleansed by combining sulphuric
acid with brine or its equivalent in a tank of water. The action of the sulphuric
acid upon the brine results in the formation of hydrochloric acid (which will
acidulate the water) and in a deposit of sulphate of soda on the bottom and sides of
the tank.
The cloth is to be submitted to this bath and worked in the usual way to cleanse
it from the lime or other soaps and other extraneous matters contained in the cloth,
after which it is drained or squeezed to express the liquor therefrom, and rinsed in
the usual way to remove all traces of the acid.
Having described in general terms the nature of my Invention, I will proceed to
give a detailed explanation of the means of carrying out the same.
In preparing the bydrochloric acid bath I take, say, forty-five pounds of sulphuric
acid (commonly known as chamber acid) of the specific gravity of 1.600, i.c., 120
Twaddle diluted to 2 Twaddle, and to this I add about fifty-four pounds of common
salt (chloride of sodium) in crystals; after stirring with a wooden rake until the salt
is dissolved, the bath is ready for use. In this bath the cloth is " worked " either by
hand or by any other well known mechanical means until the workman is satisfied,
from the appearance of the cloth, that it is cleared of soap, dirt, carbonate of lime,
and other extraneous matters. This will take place in somewhat less time than
half an hour, the bath being in good condition and the cloth of an average thickness.
It is then drawn out of the bath by means of a winch, the liquor with which it is
saturated being at the same time squeezed out by means of nipping rollers. The
cloth is next washed with water in a washing machine to remove any remaining
acid therefrom, after which it will be in a fit state for dyeing if that is required, or
for finishing in any of the various ways well understood.
In cases where the residual liquor is allowed to become a saturated solution by
additions of the above ingredients, and by the return of the liquor expressed from
the cloth on its removal from the bath, sulphate of soda will deposit on cooling the
bath, together with sulphate of lime and other matters removed from the cloth. By
separating these matters from the sulphate of soda, that substance may be utilized
as a marketable product.
The method of using the bath which I prefer after the removal of the first piece
of cloth, is to renew the hydrochloric acid by the addition of sulphuric acid and
common salt before mentioned, taking care that the latter is added in excess, viz.,
more than fifty-nine parts of salt by weight to forty-nine parts by weight of
sulphuric acid. This excess of salt is to avoid the presence in the liquor of un-
combined sulphuric acid.
If the pieces are not too bulky nor too 'dirty, six pounds of sulphuric acid and

page_text: eight pounds of common salt form a suitable charge to keep up the strength of the
hydrochloric acid bath from piece to piece.
When the action of the bath is to be accelerated, I heat it by steam or in any other
well known manner.
I would remark that the hydrochloric acid, when generated in the bath as above
explained, is far more efficient than when mixed with water in the ordinary manner.
Moreover the nascent gas is absorbed by the liquor, and no inconvenience is
experienced from the escape of acid fumes.
The sulphate of soda formed in the bath, although taken up by and partially
retained in the cloth, is not detrimental thereto, but is rather advantageous when
the cloth is to be dyed, as it acts the part of a mordant in preparing the cloth for
the dye.
Another advantage incidental to the Invention is, that the strength of the cloth
is materially increased by being subjected to this cleansing process, experiments
having proved that on an average the tenacity of the cloth is increased by some
fifteen per cent.
Having now set forth the nature of my Invention, and explained the manner of
carrying the same into effect, I claim, the cleansing of woollen cloths by submitting
the same to a hydrochloric acid bath prepared as above described, in which the
nascent acid gas is brought into contact with the goods.
In witness whereof, I, the said James Henry Rogers, have hereunto set my
hand and seal the Twenty-sixth day of April, in the year of our Lord
One thousand eight hundred and seventy-seven.
J. H. ROGERS. (L.S.)