IMPROVEMENTS IN THE PREPARATION OF COTTON FOR DYEING AND BLEACHING
Year: 1851

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
COWPER, of 20, Southampton Buildings, Chancery Lane, in the County of
Middlesex, Patent Agent, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Third day of July
(One thousand eight hundred and fifty-one), in the fifteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Charles Cowper, my exors, adiñiors, and assigns, Her especial license, full
power, sole privilege and authority, that I, the said Charles Cowper, my exors,
adñiors, and assigns, or such others as I, the said Charles Cowper, my exors,
adñiors, or assigns, should at any time agree with, and no others, from time
to time and at all times during the term of years therein expressed, should
and lawfully might make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, in the Islands of Jersey, Guernsey,
Alderney, Sark, and Man, and in all Her Majesty's Colonies and Plantations
abroad, the Invention of "IMPROVEMENTS IN THE PREPARATION OF COTTON FOR
DYEING AND BLEACHING," communicated to me by a certain Foreigner residing
abroad; in which said Letters Patent is contained a proviso that I, the said
Charles Cowper, shall cause a particular description of the nature of the said
Invention, and in what manner the same is to be performed, by an instrument
in writing under my hand and seal, to be inrolled in Her Majesty's Iligh

page_text: Court of Chancery within six calendar months next and immediately after the
date of the said in part recited Letters Patent, as in and by the same, reference
being thereunto bad, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Cowper, do hereby declare that the nature of the said Invention,
and the manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had to
the Drawings hereunto annexed, and to the figures and letters marked thereon,
that is to say:-
The Invention consists in an improved mode or modes of preparing raw or
manufactured cotton for dyeing and bleaching by submitting the same in
a close vessel, and under a pressure greater than that of the atmosphere, to the
action of water or chemical solutions, which are caused to traverse the cotton
and escape through a loaded valve or other contrivance by which the pressure
in the vessel is maintained. In the ordinary method of dyeing and bleaching
the cotton is frequently boiled in water or an aqueous solution; and one of the
effects of so boiling it is to expel the air contained in the cotton, and thus
admit of the entrance of the dyeing or bleaching solution, as well as to remove
dirt and impurities contained in the cotton." To completely expel the air by
this means a considerable time is required and fuel is expended. Now by the
Invention berein-after described the air is expelled by mechanical means, and
thus a saving of time and fuel is effected. In many cases, moreover, the
dyeing or bleaching liquids which are subsequently applied may be employed
cold, and thus a still farther saving in fuel and in apparatus may be effected.
Sheet I.--Figure 1 of the Drawings hereunto annexed is a front view, and
Figure 2 is a side view of an apparatus adapted for the purposes of the
Invention.
Sheet 2. Figure 3 is a vertical section, and Figure 5 is a sectional plan;
Figure 4 is a section of a loaded valve herein-after mentioned, drawn to a
larger scale. The same letters denote the same parts in all the Figures. a is
a strong cylindrical vessel made of copper or of plate iron tinned on the inside
and rivetted to the cast-iron foundation plate A. A flange is rivetted to the top
of the cylinder to which the cap B is fixed by bolts and nuts.
d is a cover
fitted to the cap B, and fixed by the screw 7, which passes through the nutr
and is turned by the handles i, i. The nut r¹ is secured to the cap B by the
clips C, C, which are jointed to the nut. b is another cylindrical vessel or
cistern open at the top and rivetted to the same foundation plate A.
P is a
pump with a solid plunger working through a leather collar similar to those
commonly used for hydraulic presses, and capable of being worked by the

page_text: lever P. The suction valve of this pump communicates by the pipe k with the
vessel b, while the delivery valve m communicates by the pipe n, and passages o
with the vessel a. c is a perforated plate or false bottom, which is supported by
its annular edge and by the annular projection q. It is furnished with a handle p,
and serves to distribute the liquid which enters by the passages o, as well as to
prevent those passages from being obstructed by the cotton which is placed
in the vessel a. A cock t serves to draw off the liquid from the cylinder a.
Another cock u is provided for attaching a pressure guage when required.
f is an outlet pipe communicating with the loaded valve a', which opens into
the small chamber g¹, from whence a pipe h¹ leads back into the cistern b.
The construction of this valve is shewn on a larger scale in Figure 4. a¹ is the
valve opening upwards into the chamber g¹. A rod c¹ rests on the valve, and
carries a flange e¹, which is pressed downwards by the spring y.
This spring
is inclosed in the casing or sheath h, and acts against the cap or stop 6', which
is screwed into the top of the sheath. By screwing this cap down the
pressure on the valve is increased. The upper part of the rod c¹ may bo
graduated so that the number of divisions above the cap b¹ may indicate the
pressure in atmospheres upon the valve. is a cock for emptying the pipe f,
the upper end of which is covered with a perforated plate to prevent the
entrance of solid matters. The suction pipe k of the pump is also furnished
with a perforated plate at its lower end. t¹ is a cock communicating with a
passage, for emptying the cistern b. This passage may also be covered with
a perforated plate. The pump P is provided with a safety valve a to relieve
the pressure in the event of the pipes becoming obstructed. s is a loaded
lever resting on the safety valve. The mode of using this apparatus is as
follows: The cotton which is to be prepared for dyeing or bleaching is
introduced into the vessel a, and the cover d is then placed upon the vessel
and secured by the screw r and clips C. A quantity of water is introduced
into the cistern b, and the valve a¹ is loaded to a pressure of four or five atmo-
spheres by screwing down the cap . The pump P is now set in motion and
the water is thus forced into the vessel a until the pressure is sufficient to open
the valve a', when the air and water pass out together through the valve a¹,
chamber g', and pipe h'. The water falls again into the cistern b, while the air
escapes. The pump being kept in motion forces the water again into the
cylinder a, while the air and water continue to escape at the pipe h', and thus
the air is speedily extracted from the cotton, which becomes thoroughly satu-
rated with water. By stopping the pump from time to time, and examining a
pressure guage attached to the cock u, it will be found that the pressure varies
at the commencement of the operation, but remains constant when all the air

page_text: is expelled. In acting upon one hundred pounds weight of cotton, thread, or
cloth in this apparatus, the operation may be completed in forty or fifty
minutes, and the cotton is then removed from the apparatus, and is fit to
be dyed or bleached in the ordinary modes; but as herein-before mentioned,
the dyeing or bleaching liquids may be used cold in many cases in which they
are now used hot. There is thus not only an economy of fuel and apparatus,
but also the injurious effects of some solutions, when heated, upon the fibre
and lustre of the cotton are avoided. If desired, however, the water or
solutions used in the apparatus may be employed in a warm or heated state.
In some cases, as for instance when large quantities of dirt or impurity are
to be removed from the cotton, it is advantageous to conduct away the water
issuing from the pipe ', instead of allowing it to return into the cistern b,
which is then supplied with fresh water. In lieu of removing the cotton from
the apparatus to place it in the mordants or dyeing or bleaching liquids, those
liquids may be introduced into the cistern b, and forced through the cotton by
means of the pump, after having first saturated the cotton with water, as
above described. Or the saturation with water may be omitted, and a
solution of a mordant, or other solution employed in lieu of it, taking care to
pump or force the solution through the cotton until the air has been driven
out at the valve a¹.
In preparing cotton cloth which is to be dried previous to being dyed cold
with indigo, it will be found advantageous to saturate it in the apparatus
above described with a solution or milk of lime containing from one half to
four per cent. of lime, and afterwards to immerse it in dilute sulphuric
acid, containing one per cent. of acid. Cotton may be bleached by saturating
it with water in the apparatus herein-before described, and immersing it for ten
or twelve hours in the milk of lime above mentioned, then washing it and
immersing it for an hour or an hour and a half in a solution of chloride of
lime, and then again washing it and passing it through dilute sulphuric acid,
containing one per cent. of acid; and lastly, washing and dyeing it.
It is evident that the apparatus herein-before mentioned may be modified
in its form and arrangement, and in lieu of obtaining the requisite pressure by
means of a pump, it may be obtained by admitting the water in solution into
the vessel a, from an elevated cistern, or by other means.
In like manner,
in lieu of employing an escape valve loaded with a spring or a weight, a small
opening regulated by a cock or valve may be used, provided care be taken
that the opening is not so large as to prevent the pressure in the vessel a from
rising above that of the atmosphere. Another mode of allowing of the escape
of the air and the water is to cause the pipe to dip into a yessel of mercury

page_text: to a sufficient depth to maintain the requisite pressure. In whatever manner,
however, the apparatus may be constructed, it must consist merely of a close
vessel in which the water or solution may be made to traverse the cotton
under a pressure greater than that of the atmosphere, and pass off,
carrying away or expelling the air which may have been contained in the
cotton.
Having now described the nature of the Invention, and the manner in
which the same is to be performed, I wish it to be understood that I do not
confine myself to the precise form and materials of the apparatus herein-
before described. But what I claim is, the mode or modes of preparing
cotton for dyeing and bleaching, by placing it in a close vessel and forcing
through it water or a solution of a mordant or other solution, the escape of
which is permitted and regulated by a loaded valve or otherwise, in such a
manner as to maintain a greater pressure in the close vessel then that of the
atmosphere, as herein-before described.
In witness whereof, I, the said Charles Cowper, have hereunto set my
hand and seal, this Second day of January, in the year of our Lord
One thousand eight hundred and fifty-two.