Improvement in the Manufacture of Refined Indigo.
Year: 1893

page_text: Date of Application, 18th Jan., 1893
Complete Specification Left, 18th Nov., 1893-Accepted, 17th Feb., 1894
PROVISIONAL SPECIFICATION.
Improvement in the Manufacture of Refined Indigo.
SAMUEL JOSEPH SIMPKIN Chemist (in Indigo Works) 10 Sunny Bank Leeds
do hereby declare the nature of this invention to be as follows :—
The manufacture of refined indigo in an atmosphere which is not capable of
oxidising. I use any of the known methods for the reduction of the crude indigo
(as imported) and perform the operation in a pan or vessel which is air tight and into
which I can introduce a non oxidising gas at will.
jacketed so that the operation can be facilitated by raising the temperature to the
prefer the pan or vessel to be
required degree. The separation of the clear solution of white indigo is effected by
decantation or by filtration in an atmosphere which is not capable of oxidising.
The indigo contained in the solution is precipitated by oxidation filtered out
and dried.
For the atmosphere I use a gas such as coal gas, nitrogen gas, hydrogen gas or
any admixture of these but do not claim these or any admixture of them
exclusively but use any gas or mixture of gases which do not possess oxidising
properties.
Fahma 01. 1000
1 SAMUEL JOSEPH SIMPKIN Chemist (in Indigo Works) 10 Sunny Bank Leeds
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 :-
The manufacture of refined indigo in an atmosphere which is not capable of
oxidising. For the atmosphere I use a gas such as coal gas, nitrogen gas, hydrogen
gas or any admixture of these, but do not claim these or any admixture of them
exclusively, but any gas or mixture of gases which does not possess oxidising
properties.
use any of the known methods for the reduction and solution of the indigo
contained in the raw material (as imported) and perform the operation in a pan or
vessel which is airtight and into which I can introduce a non oxidising gas or
mixture of gases at will. I prefer the pan or vessel to be jacketed so that the
operation may be facilitated by raising aud keeping the temperature to any required
degree. For this purpose I circulate in the space steam, hot air or hot water.
This apparatus is shown in the accompanying sketch. V is the vessel in which the
operation is performed and is fitted with an agitator A worked by the gearing G G.
Jis the jacketed space for the circulation of heat. T is a tube through which I
regulate a flow of the gas already described, in the sketch two tubes are shown
one is for connection to another pan when more than one is required. B is a
syphon pipe through which the charge is entered. C shows the position of the
cock for drawing off the clear solution of indigo white. D is for the withdrawal of
the refuse or in the case of using a filter press, instead of decantation, for
attachment.

page_text: As an example of the manner in which 1 perform an operation, the vessel is first
filled with the gas already described, then I enter through the syphon pipe B
100 lbs. of raw indigo, finely ground in water, 200 lbs. ferrous sulphate dissolved in
water & 80 lbs. of lime made into a thin milk of lime all of which are thoroughly
mixed by the agitator, the vessel is then filled with hot water which dissolves the
white or soluble indigo.
I do not bind myself to these proportions or this method of reduction as I can
make the reduction of the indigo by the hydrosulphite obtained from the
decomposition of sulphites by zinc.
The separation of the clear solution of white indigo is effected by decantation
or it may be accomplished by filtration in an atmosphere which is not capable of
oxidising. The indigo contained in the solution is precipitated by oxidation filtered
out and dried.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed declare that what I
claim is
The production of pure or refined indigo having a greater dyeing power and
brilliance, and also, a greater yield from a given quality of the raw material and a
saving of time in production.
Dated this 17th day of November 1893.
SAMUEL JOSEPH SIMPKIN.