Improvements in the Manufacture of Indigo by the Application of Electricity.
Year: 1889

page_text: Date of Application, 29th Aug., 1889-Accepted, 5th Oct., 1889
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Indigo by the Application of
Electricity.
1, FRANK HUGHES, of the firm of Hughes, Eli, & Hughes, of 76 Chancery Lane
London W.C. Patent Agents, do hereby declare the nature of this Invention, (a com-
munication to me from abroad by Æneas John McDonald, residing at Moorla Factory
Champarun, Bengal, East Indies, Indigo Planter) and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement, that is to say :-
My improved method of causing the quicker and more complete precipitation of
Indigo by Electrolysis has for its object the increased yield of Dye substance and
improvement in the Colour and quantity of Indigo. The following is a succinct
description of the process I employ in carrying out my Invention.
Having placed two electrodes of a suitable metal or metallic substance in the vat of
Indigo, I join one plate up to the positive pole of the battery or Dynamo, and the
other plate to the opposite pole. I then cause a current of electricity to flow or pass
from the one plate to the other through the Indigo solution or fluid in the beating
vat during the beating process the electrical action of the current during its passage
from one plate or electrode to the other, causes a more rapid and thorough disintriga-
tion of the Indigo grain. This electro chemical action assists the formation of the
grains of Indigo by separating them more perfectly from the vat liquor and
precipitating the Indigo more readily than by existing methods.
By adoption of my new mode, there is also a saving in the wear and tear of
machinery, inasmuch as the speed of the beating wheel may (without increasing the
time required to beat up a vat) be reduced, and the grains of Indigo are not smashed,
but formed large, and all are precipitated with less waste than by any other known
process.
The passage of an electric current, whether from galvanic batteries or cells of
whatever description, or from a dynamo machine driven by steam or water power or
any other power usually applied to mechanical purposes, or from a magneto electrical
machine driven by any of the above mentioned sources of power or from a thermo-
electric pile, through a vat of Indigo during the process of beating causes a quicker &,
more thorough deposition of the Indigo grain.
By my Invention I may use electrodes of zinc, iron, tin, copper, silver, platinum,
or any metallic substance capable of conveying a current of electricity, also an
electrode of carbon, graphite, coke, or any of the non metallic conductors of
electricity.
I further may use a current of electricity flowing either in the same direction as
the flow of the stream or current of water in the vat caused by the process of beating
or in the reverse direction.
The electrodes I employ are placed at a suitable distance from each other in the
beating vat to assist the passage of a current of electricity.
I find that alkaline compounds or acids placed in the water lessen the resistance
to the passage of the electric fluid, but I do not claim the use thereof as electrification
may be resorted to without or in addition to the alkaline compounds or acids.
My improved method of causing the quicker and more complete precipitation of
Indigo by Electrolysis has for its object the accelerated disengagement of Carbonic
and other gases with which the fermented liquor drawn off the several steeping vats
and collected in the beating vat, is charged, hastening the formation and agglomeration
of the flecks of Indigo, and ultimately their more complete precipitation to the bottom

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 I
claim is:
1. The method above substantially described of treating indigo and causing a
quicker & more thorough and increased deposition of the indigo grain in the Manu-
facture of indigo by the application of an electric current through a vat of Indigo
during the process of beating substantially as above described.
2. The right to use in the manner indicated a current of electricity flowing either in
the same direction as the flow of the stream or current of water in the vat (caused by
the process of beating) or in the reverse direction as and for the purposes stated.
3. The combination substantially hereinbefore set forth of electrodes, and other
means, of passing a current of electricity through and acting on a vat of Indigo,
substantially as described.
4. The process, or new and particular method of applying electrodes from which the
current may flow in either direction, by which the special effects above mentioned are
produced.
5. The application of the electric current flowing in either direction in combination
with the liquor of an Indigo vat provided with electrodes and with or without a
beating wheel, all constructed or placed and operated substantially as described.
6. The above described improved mode of using the electric current for the
purposes hereinbefore mentioned, viz.: by the introduction of a current of electricity
into the beating vat to aid the deposition of Indigo and to cleanse the liquor thereof
substantially as described.
Dated this 90th day of August 1889
HUGHES, ELI & HUGHES,
76, Chancery Lane, London, W.C., Agents for the Applicant.