Improvements in or relating to the Process of Indigo Dyeing, and to Apparatus Employed therefor.
Year: 1894

page_text: Date of Application, 25th Aug., 1894
Comp ete Specification Left, 27th May. 1895-Accepted, 29th June, 1895 --
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Process of Indigo Dyeing, and
to Apparatus Employed therefor.
I, JOHN WILLIE SANDERSON, of 3, Portobello Terrace, Wakefield, in the
County of York, Dyer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to the process of indigo dyeing, and to apparatus employed
therefor. The objects in view are to economize in the quantity of indigo found
necessary in the ordinary process of indigo dyeing, as practised previous to my
invention hereof, and also to perform the operations more rapidly and efficiently
than has hitherto been done by the said ordinary process.
"
In the ordinary process, as formerly practised, machines known as "hawking
machines are employed for indigo dyeing. In this machine rollers (called nipping
rollers) are arranged and adapted to rotate within the vat containing the dye liquor
in such a manner as to draw the fabric operated upon into the liquor to be dyed.
After the fabric has been immersed a certain period, (usually half an hour), it is
removed from the liquor, folded, and squeezed between a pair of narrow nipping
rollers (or wringing machine) of rubber, mounted above the vat, to expel the
liquor. The fabric is then opened out on the floor and allowed to remain there
exposed to the air for a few minutes, after which it is returned to the dye vat and
again immersed in the liquor to obtain the depth of colour required. As soon as
the fabric has been sufficiently dyed, it is again passed through the wringing
machine to remove the dye liquor.
By my invention the fabric is drawn into the dye vat by the nipping rollers in
the usual manner, and then raised out of the liquor and passed between rollers
mounted above its surface, in order to press or squeeze the fabric; whereby the
surplus liquor is expelled from, and air is admitted to, the interstices of the fabric;
and the fabric is again passed into the liquor. This operation is done in a
continuous manner, (instead of in an intermittent manner as hitherto practised),
and repeated until the fabric is sufficiently coloured. It is found in practice that
my improved operation more effectually dyes the interior of a thick material in
much less time, and with a great saving in indigo, as compared with the ordinary
process of indigo dyeing.
But
For the mechanical operation of squeezing the fabric to expel the liquor, and to
admit air to the interstices of the fabric, rollers, operating above the surface of the dye
liquor and between which the fabric is caused-to pass, are the most convenient.
I do not confine myself to any particular method of performing the said mechanical
operation, nor to any particular number or arrangement of rollers. It is important
however, that where outside rollers are employed they should be so arranged, or
of such proportions, or driven at such-a rate of speed, that the fabric is moved at
a corresponding speed to those already referred to as nipping rollers, in order that
the fabric may be moved at a uniform speed throughout. Otherwise, the fabric
might easily be torn if the leading rollers were driven too fast, or if too slow, the
fabric would overrun, and so cause difficulties in the dyeing operation.
A-convenient means for performing the said mechanical operation of squeezing
the fabric after immersion is to mount a pair of nipping rollers above the surface
of the dye-liquor and--arrange- them to work in suitable-bearings, and -adapt them

page_text: to be driven by a belt or other suitable means from an outside pulley on an axle of
one of the rollers working in the vat. By making all the rollers of the same
diameter, and the driving and driven pulleys of equal diameter, and connecting
them by means of a strap or belt in a manner well known to engineers, the desired
object is attained. If the ends of the piece of fabric to be dyed are sewn together,
after being passed through the rollers, it forms an endless web of cloth, and during
my improved operation it is kept in continuous movement, part of it passing
through the dye liquor and part of it through and opened out to the action of the
atmosphere, at the same time.
It is to be noted that my invention, as herein described, has been published in
fraud of me by an application dated 18 May 1893, No. 9938.
Dated this 25th day of August 1894.
FAIRFAX & WETTER,
433 Strand, London, Agents for the Applicant.
Improvements in or relating to the Process of Indigo Dyeing, and
to Apparatus Employed therefor.
I, JOHN WILLIE SANDERSON, of 3 Portobello Terrace, Wakefield, in the
County of York, Dyer, 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 :-
My invention relates to the process of indigo dyeing, and to apparatus employed
therefor. The objects in view are to economise in the quantity of indigo found
necessary in the ordinary process of indigo dyeing, as practised previous to my
invention hereof, and also to perform the operations more rapidly and efficiently
than has been done by the said ordinary process.
In the further description of the invention, reference is made to the accompanying
drawings, in which Fig. 1 is a sectional elevation of a "hawking" machine, such
as are employed for indigo dyeing, but having my improvement embodied therein;
and Fig. 2 is a plan thereof.
The machine is mounted upon and partly within a vat a of suitable dimensions
which contains the dyeing liquid, not shown. In this machine, nipping rollers b, b,
are shown as working in a framework c, and adapted to rotate within the vat a and
to draw the fabric d, placed between the rollers b, into the dye liquor to be dyed.
After the fabric has been immersed the required period, (usually half an hour), it
is removed from the liquor, folded, and squeezed between a pair of narrow nipping
rollers (or wringing machine) of rubber, mounted above the vat, to expel the liquor.
These rollers are not shown in the drawings. The fabric is then opened out on
the floor and allowed to remain there exposed to the air for a few minutes, after
which it is returned to the dye vat and again immersed in the liquor to obtain the
depth of colour required. As soon as the fabric has been sufficiently dyed, it is
again passed through the wringing machine to remove the dye liquor. The above
is the ordinary process, as formerly practised, and I make no claim thereto.
By my invention the fabric d is drawn into the dye vat a by the nipping
rollers b, b, in the usual manner, and then raised out of the liquor and passed
between two rollers e, e, mounted in a framework fabove the surface, in order to
press or squeeze the fabric and expel the surplus liquor therefrom, and also to admit
air to the interstices of the fabric; whereby the dyeing operation is hastened.
After exposure to the air the fabric is again passed into the liquor, but it
is to be noted that the operation is done in a continuous and automatic manner,
(instead of in an intermittent manner, with hand labour, as hitherto practised),
and repeated until the fabric is sufficiently coloured. This is accomplished by

page_text: passing the fabric d between the nipping rollers b, b, the outside rollers e,.e, and
over a guide roller g; also placed outside of the liquor, and joining the ends of the
fabric so as to form an endless band or web of cloth, which is kept in continuous
movement, part of it passing through the dye liquor and part of it through and
opened out to the action of the atmosphere, at the same time.
The rollers e, e, perform the mechanical operation of squeezing the fabric to
expel the dye liquor, and, assisted by the guide roller g, the fabric is stretched and
opened out to admit air to the interstices of the fabric, as shown in Fig. 1.
A pair of fast and loose pulleys li, h, are shown as mounted upon the side of the
vat in any suitable manner, as the means of driving the rollers. On their axle i is
mounted a sprocket or chain wheel; and a small pinion k, the latter gearing into a
toothed wheel 1, mounted on a shaft m, having another toothed wheel 'n secured to
the shaft m at the opposite side of the vat a. At the same end, the nipping
rollers b, b, are geared together by pinions o, and one of them is driven by the
toothed wheel n; so that the fabric d' is drawn between the rollers b, b, when they
are closed upon the same by the adjusting hand wheels p, p, which, acting upon the
sliding bearings of one of the rollers in the framework c, nip the fabric and draw it
beneath the surface of the dye liquor.
and screws
In
The upper outside roller e is made adjustable by the handwheels
acting upon its bearings sliding in the framework f, so that the fabric d is subjected
to the necessary pressure for squeezing the liquid out of it. But to avoid any
undue strain upon the fabric, the lower roller e is driven from the sprocket wheel j
by the chain belt r passing over another sprocket wheel s secured to the axle of
the lower roller e, and the circumferential speeds of the nipping rollers b, b, and
the outside rollers e, e, are required to be exactly the same, so that the fabric dis
moved at a uniform speed throughout; otherwise the fabric might be torn.
the drawings the sprocket wheels and sare not exactly the same diameter, but the
difference in speed that would otherwise result is compensated for by differences in
the gearing k, l, or it may be n. Or sometimes I make the rollers b, b, and e, e, of
the same diameter, and also the driving and driven pulleys or wheels of the same
diameters, connecting them by a suitable belt, or in any other manner well known to
engineers, in order that the fabric may be continuously driven through the dye
liquor, squeezed above its surface, and exposed to the air before again entering the
dye vat, without undue strain. The guide roller g serves to extend the fabric
and prolong its exposure to the atmosphere in its continuous travel, but may be
dispensed with if a sufficient exposure is provided for otherwise.
The framework c is shown as bolted to the sides of the dye vat a and hung upon
the shaft m; but the bolts are sometimes dispensed with, so that the framework &
with the nipping rollers b, b, may be swung upon the shaft m, and so brought to
the surface if required.
It is to be noted that I do not confine myself to the particular method of
squeezing the liquid from the fabric, nor to the number or arrangement of the
rollers, nor to the particular method of driving the same; and also that my inven-
tion has been published in fraud of me by an application dated 18th May 1893,
No. 9938.
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. An improved process of indigo dyeing consisting of a continuous operation of
immersion in the dye liquor, squeezing above its surface, and exposure to the
atmosphere of an endless band or web of fabric, until the desired depth of colour
has been obtained, substantially as and for the purpose herein described.
2. The herein described improved apparatus for indigo dyeing consisting of a
dye vat having nipping rollers therein adapted to operate upon an endless band or
web of fabric to continuously draw it beneath the surface of the dye liquor
combined with outside rollers arranged and operating to continuously squeeze the

page_text: surplus liquor from the fabric and expose it to the atmosphere during its travel,
and means for driving the nipping rollers and the squeezing rollers at the same
circumferential speed, substantially as and for the purpose shown and specified.
3. An improved indigo dyeing apparatus arranged and operating substantially as
and for the purpose herein described and shown in the drawings.
Dated this 25th day of May 1895.
FAIRFAX & WETTER,
433 Strand, London, Agents for the Applicant.