Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
BACKGROUND OF TI~E INVENTION
1. Field of the Invention
This invention relates to a process for the treatment
of elongate members, for example the dyeing of yarn and to
apparatus for carrying out the process. `
2. Summary of the prior art
It has already been proposed in French Patent Publication
No. 2,098,482 and its patent of addition publication No.
1,122,708 (Omni~ de Prospective Industrielle) to provide a
process and apparatus enabling the impregnation, in particular
dyeing, of yarn. According to this prior process, yarn was
passed with continuous rectilinear displacement through a
liquid bath, for example of dye and special devices were
provided to eliminate the excess of liquid and to dry the
yarn.
Similar processes are also described in French Patent
Publication No. 2,249,312 (Maschinenfabrik Rutl AGj and U.S.
Patent Specification No. 3,739,746 but these previously pro
posed processes are intended to obtain total and uniform
impregnation of the yarn by the treatment liquid, and it
follows that the provision--of certain special effects, such
as are currently required by users, cannot be performed.
An object of the present invention is therefore to
provide impregnation for a yarn by a liquid, for example
a dye, enabling the ready production of a large variety
of special effects, for example, flecking.
SUMMARY OF THE INVENTION
According to the present invention, apparatus for treating
a continuously moving yarn with an impregnation liquid su
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as a dye comprises means defining a substantially closed treat-
ment chamber having an inlet and an outlet for the yarn,
atomizer means having a slot nozzle for applying an airless
mist of the liquid to the yarn in a plane perpendicular to the
path of the yarn, and means for supplying the liquid to the
atomizer means and for removing unused liquid from the chamber.
BRIEF DESCRIPTION OF T~E DRAWINGS
One embodiment oE the invention will now be described,
by way of example, with reference to the accompanying drawings,
of which:-
Figure 1 is a diagrammatlc view of apparatus embodyingthe invention;
Figure 2 is a diagrammatic section of a recovery
vessel forming a part of the apparatus of Figure l; and
Figure 3 is a fragmentary elevation showing a
device for preventing the formation of fluff pads at the
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entry to a treatment cham~er of the apparatus of Figure
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Referri~g to ~igure 1 9 it will be seen that the
treatment apparatus 9 for example for dyeing, comprises
two treatment chambers 1~ through which pass four threads
or yarns 2~hereinafter referred to as "yarns") moving in
a continuous man~er by means of appropriate drawinK
means (not shown) perpendicularly to the plane of the
Figure. ~he two treatme~t chambers 1 are identical
and the number of threads or yarns which transverse them
can be selected as desired.
Each treatment chamber 1 is constituted by a lower ~`
receptacle (or other part) 3 secured to a framework of
the apparatus and is surmounted by a cover (or other
part) 4 suspended from a gantry or other support struct-
ure 5,the height being adjustable with ~he aid of
uprights 6 rigid with the framework. ~hus each treatment
chamber i~ co~stituted by two telescopic parts the
assembly being closed, although not ln a fluid-tight
ma~ner, with respect-~ the ambient.
~ he inlet and outlet pas~ages 7, 8 for the yarns
2 are respectively provided opposite one another in
the two lower parts 3 while an atamizer 9, ~ecured to the
gantry 5 is mounted at the top of each upper p~rt or
cover 4.
At the lower part Or each lower part or receptacle
3 a liquid outlet pipe 5 serves to discharge the latter
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and communicates with a recovery vessel 11 sho~/n in detail
in Figure 2. It iæ constituted by a vessel open to the
ambient and has internally a grill or other perforate
means 12 which supports seveIal layer~ of balls 1~. ~he
latter have a small diameter preferably lying between
5 and 10mm and are preferably of glass. It is furthermore
desirable that the overall thickness of the layers of
balls should be at least 5cm.
The outlet pipe 10 discharges JUSt above the
grill 12 after having passed substantially through the
layer of balls 13.
At the lower part of the vessel 11 there is
disposed a return pipe 14, prov~ded with a control valve
15 and termi~ating at an operating vessel 16 arra~ged
adjacent the suction pipe of a pump 17.
A reserve vessel 18 is connected to the operating
vessel 16 by a pipe 19 provided with a control valve 20
~he operating vessel 16 is maintained at a constant
level and is supplied from the reserve vessel. Means,
(not shown) serve to maIntain the liquid level constant.
The pump 17 comprises a discharge pipe 21 having
a pressure ~auge 22 and terminating at one Or the
atomizers 9. ~he latter are provided in order to produce
atomization of liquid in known manner, and further
reference will be made to the atomizers hereinafter.
~ inally, for each chamber a by-pass pipe 23 is
provided a~d has a control valve 24. The by-pass
provides for communication between the lower part of
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each receptacle ~ of the treatment chambers a~d the pipe
21. With this arrangeme~t, it is po~sible to effect
recycling of the treatment liquid directly from the pump
to the recovery vessel without passage through the
atomizer.
It is necessary to emphasise that the atomizers,
of known type, haYe an outlet slot delivering a mist of
fine droplets of completely de-aerated liquid. More
accurat~ly, the atomization produced by the atomizer does
not introduce into the liquid any paras~té air so that the
atomized mist is precisely controlled and i8 homogeneous.
The slit nozzle of each atomizer is so disposed that the
pla~e of the atomized mi~t is perpendicular to the path
of the yarn, and is defined by the inlet and outlet 7
and 8.
It will be noted in this respect, for the given
dimensions of the slot of the atomizer, an increase i~
the supply pressure of the liquid enables an increase in
the fineness of the droplets of the atomized mist. ~hus
for the supply pressure of 1 kg/cm2, the"degree of
coverage" of the yarn is of the or~er of 30% whilst
it will reach 80% for a pressure of 6kg~cm2. It will
be recalled that the "degree of co~erage" is defined
as the ratio between the surface of the treated yarn
(dye) and the total surface of the yarn~
Similarl~ modification of the dimensions of the
slot of the atomizer enables variation in the "density"
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of the liquid mist. For a ~iven supply pressure, the
smaller the dimensions, the more the mist will be con-
centrated.
'rhe operation of the apparatus will be apparent
already to the man skilled in the art, but several
particular points will now be explained.
The control o~ the height of the gantry 5 enables
modification of the density of the region of the atomized
liquid traVersed by -the yarn. '~hus, for a given velocity
of displacement of the yarn, it is possible to obtain a
variation in the number of droplets of liquid encountering
the yarn, and as a result, a number of special effects
can be achieved particularly if the liquid is a dye. ;
Variations in the special effects may also be provided by
means of horizontal displacement of the passages for inlet
and outlet of the yarns with respect to the vertical plane
passing through the slit of the atomizer. It is also useful
to note that variations, possibly periodic, in the velocity
of the displacement of the yarn (for example betwee~ 200
and 900 m/minute) in the supply pressure of the atomizer
(for example between 1 and 6 kg/cm2) will enable the
pro~ision, particularly when they are carefully combined9
of original special effects.
Finally9 it is evident that several apparatus for
treatment may be placed in succession along the path'~
of the yarn, each of them enabling the applicatio~ of a
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dye of predetermined colo~r or any other appropriate
treatment.
On the other hand, it is important to maintain the
dye at a constant humidity value, in the absence of which
the distribution of the dye on the yarn or other elongate
me~ber will not be homogeneouq.
~ o this end, the treatment in the substantially
closed chamber substantially eliminate~ all air
circulation, so that all the atmosphere exi~ting withi~
the installation abo~e the treatment liquid will become
saturated very rapidly. ~his is the case for the operating
vessel 16 and, it should be understood, as will be
apparent, also for the chambsr 1.
With regard to the recovery vessel 11, it ha~ been
established that the presence of the layers of balls 13
prevents evaporation which would otherwise occur in the
presence o~ fresh air above the free surface of the liquid
in thi~ vessel. ~he layers of balls enable however the ;
necessary maintenance of atmospheric pressure in this
part of the installation. The ~alve 15 of the return
pipe 14 enables emptyinæof the treatment circuit.
An important problem has also been resolved i~ the
preferred embodiment. In practice, it may happen, duri~g
the treatment of certain yarns, that an accumulation of
fluff builds up at the inlet 7. The fluff accumulate~
and forms a pad which absorbs the treatment liquid flowing
down the interior walls of the chamber 1. ~he yarn which
traverses the pad thus becom~ charged with treatment
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liquid before traversing Ghe mist of atomized liquid.
~he products will then have non-acceptable defects.
In order to avoid these disadvantages, the inlets
7 are each defined by a tube extendi~g into the interior
of the treatment chamber, the internal extremity bein3
chamfered and provided with a gutter or deflector 7a
shown in Figure 3. Liquid trickling down the walls of
the chamber will not therefore come into contac-t with
the yarn before it has traversed the mist of atomized
liquid.
Similar devices are provided for the outlets 8
since the same phenomenon may occur there.
It will be desirable, however, to avoid the
formation of fluff which arises by the detachment of
fibrils from yarn, for example by electro-static
action and/or mechanical action during the traversing of
the tubular passages such as provided at the inlet 7.
To this end and as shown in Figure ~, there is
arranged upstream of the i~let to the treatment ch~mber,
a device enabling the avoidance of the accumulation of
fluff. ~ settling chamber 25, surrounds the inlets 7
and comprises simply a closed casing of which the upper
surface is constituted by a grid 26. ~he length of the
casing 251 in the direction of movement of the ~arn 2,
is preferably at least equal to 15 times the diameter of
each inlet 7. ~he walls of the casing have a sufficient
height, preferably at least equal to ten times the diameter
of each inlet 7.
It should be understood, that the wall of the casing
25t opposite the chamber 1, comprises an inlet orifice
assembly 27 of which the inter~al diameter is preferably
approximately that of each inlet 7c '~he orifice
assembly 27 is defined by annular section nozzle~ closed
at the side of the settling chamber~ and constituted
preferably by two co-axial tubes 28 and 29. At the
outside of the settling chamber, the outer tube 28 has a
length in excess of that of the inner tube 29. A
distance between the outer ends of the tubes 28 and 29,
approximately equal to the diameter of the tube 28t gives
good results. ~ pipe 30 discharge~ into the ~mular
section space of the nozzle assembly 27 and delivers
pressure air under low pressuret approximately 0.5 bar~
During operation, the pressure air removes the
fibrils which are not adequately adhered to the yarn which
can then really traverse the inlet orifice 27,then the
settling chamber 25t and finally the inlet 7 without
causing the accumulation of fluff.
Example
- The process in accordance with the invention was
applied to the impregnation by a dye of four acrylic yarns
of high bulk of dernier ("titrage")Nm 2.16. ~he yarns
were disposed as groups of two beneath a single atomizer.
Practical conditions were as follows:
- velocity of the yarns; 600 metres per minute;
- atomizer (reference 100/15~ of the company
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Kremlin of ~ille, ~rance)
- jet opening: 75
- supply pressure of the atomizer:6 kg/cm2
- distance between the atomizer and the yarn;
250 mm.
- distance between the yarns of a given group:
6 mm.
- mean distance between the two groups of
yarns:60 mm
It was found that the "degree of covering" was
of the order of 80% in the form of very fine a~d very
homogeneous drops. The quantity of liquid used per
kilogram of yarn wa~ 120 grams for a "amount of deposit"
of 12%.
/RD,
