FORM 2
THE PATENT ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION (See section 10 and rule 13)
TITLE OF THE INVENTION:
A device to open wet staple fibre and form a uniformly loosened fibre mat.
APPLICANT:
Aditya Birla Science and Technology Company Pvt. Ltd., Plot number 1 and 1-A/l, Taloja,
MIDC, Taluka- Panvel, District- Raigad- 410208, Maharashtra, India.
PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes this invention and the manner in which it is
to be performed.

FIELD OF THE INVENTION
This invention relates to a device to open wet staple fibre and form a uniformly loosened fibre mat. The invention also relates to a method for opening wet staple fibre to yield a uniformly loosened fibre mat.
BACKGROUND OF THE INVENTION
Generally, in the solvent spun fibre process, after the fibre has been cut into desired length, the staple fibre moves to a wet fibre opening and mat forming unit along with a large quantity of dilute solvent stream. The fibre gets dipped into the pooled dilute solvent bed and is then opened with the help of steam or compressed gas sparging inside the trough. The staple fibres which are around 5% of the dilute solvent (w/w) follow the streamline of continuous phase of solvent stream and get distributed in the trough. Once the wet fibre gets distributed inside the trough, steam or compressed gas sparges from the bottom of the trough in cross flow manner through a sparging unit to open the wet staple fibre. As the fibre moves forward in the trough, a mat of opened fibre is formed after percolation of dilute solvent stream which is passed through the end of the unit via conveyor belt.
A major drawback of the mat forming unit used conventionally is its prevalent design which does not enable uniform opening of the staple fibre. This creates difficulty in further treatment such as washing, bleaching, oil treatment, drying etc. Here, the trough width is kept same as the after-treatment machine width in order to meet the desired production along with specific fibre loading. Non-effective sparging and distribution of wet staple fibre causes fibre entanglement which leads to lump formation which in turn affects further treatment process. A second- problem incurred when employing the method and device of the prior art is in the consistency of the strand and mat produced. Since in the prior art, the fibre lumps are not minimized, the final fibre mat produced is not uniform. In conventional process, steam is

excessively used to open the wet staple fibre and sometimes this ratio of steam to fibre is around 2:1, to get the effective fibre opening. This required high energy consumption and hence, low efficiency. Further, high steam velocity results non-uniform distribution of mat which affects other quality parameters like moisture variation and oil-pickup unit variation.
It is, therefore, a purpose of the present invention to provide a method for preparing a uniform fibre mat and to produce a mat that comprises well opened fibres. There is also a need for a device which provides operational parameter range that enables uniform opening of the mat and form a uniform fibre mat with minimum wet fibre lumps in it. Furthermore, there is a need for a method which consumes less energy instead of steam energy for effective and uniform opening of the fibres such that minimum fibre lumps are left during fibre mat formation. Lastly, there is a need for an efficient device and method of uniformly loosening fibres to form a fibre mat which leads to reduction in overall cost of the fibre.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic representation of a device for opening wet staple fibre to yield a uniformly loosened fibre mat according to an embodiment of the present invention.
SUMMARY OF THE INVENTION
According to an embodiment of the invention, there is provided a device for opening wet staple fibre to yield a uniformly loosened fibre mat comprising:
a) a fibre feeding arm movable up to 45° with reference to the central axis of a trough for introducing a mixture of staple fibre and dilute solvent into the trough;
b) a distributor plate encasing the said arm defining a gap of 50mm to 300mm between the said plate and the said arm, the said arm being oriented at an angle of up to 45° from the horizontal axis of a base plate, the slope of the said distributor plate being

2° to 15° with reference to the base plate for uniform distribution of the fibre-solvent slurry across the said trough;
c) a sparging zone comprising a plurality of spargers arranged sequentially where each sparger has a plurality of orifices oriented in staggered pattern releasing a pulsating stream of compressed gas into the fibre-solvent slurry to open wet staple fibre in the said slurry stream; and
d) a fibre stabilizing zone for fibre mat formation comprising a means for obtaining a desired fibre bed height.
According to another embodiment of the invention, there is provided a method for opening wet staple fibre to yield a uniformly loosened fibre mat, the method comprising:
a) dispensing a mixture of staple fibre and dilute solvent into a trough;
b) injecting a pulsating stream of compressed gas into the slurry through the orifices of multiple spargers;
c) forming a uniformly loosened fibre mat,
wherein the orifices of the spargers are positioned relative to each other such that bubbles of compressed gas emerging from any orifice do not coalesce with the bubbles emerging from any adjacent orifice.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a device to open wet staple fibre to yield a uniformly loosened fibre mat and a method to carry out the same. The main purpose of the present invention is to provide a device and method which uniformly opens the wet staple fibre which minimize the possibility of lumps formation.
According to the device of the present invention, as more clearly illustrated in Figure 1, a mixture of staple fibre and dilute solvent (101) is fed into the device of the present invention

which is dispensed through a feed line (103). which may be rectangular or circular in shape. Thereafter, the said fibre-solvent slurry (101) enters a dome (104) which aligns all the said fibre-solvent slurry (101) stream into a single flow path. The said fibre-solvent slurry (101) is then fed into a fibre feeding arm (105) which ensures uniform distribution of the said fibre-solvent slurry (101) on a distributor plate (106). Depending upon the length of the said fibre feeding arm (105) and the trough width, the movement of the said fibre feeding arm (105) should be up to 45° from the central axis of trough. Further, the said distributor plate (106) is placed at an angle between 2° to 15° to distribute the said fibre-solvent slurry (101) uniformly across the said trough. The said fibre-solvent slurry (101) then travels through a falling zone (107) which can be either disposed vertically or at some inclination. In a preferred embodiment, the said falling zone (107) is designed in such a manner that there is a slope formed at the angle between 10° to 40° and a height between 150mm to 300mm for better distribution of the said fibre-solvent slurry (101).
The said fibre-solvent slurry (101) thereafter travels through a sparging zone (108). In a preferred embodiment, the said sparging zone has a length between 1.5m to 3m. Various rectangular or circular spargers are spread across the said sparging zone (108) which in turn bubbles compressed gas or a combination of steam and compressed gas into the slurry. The bubbles collide with the wet fibre and transfer their energy to the wet staple fibre enabling the wet staple fibre to open. The bursting of pulsating bubbles provides onset turbulence to the wet fibre which in turn helps in removal of fibre lumps. The orifices of the spargers are positioned in a staggered pattern such that the said compressed gas bubbles arising out of one orifice do not collapse or collide with the bubbles of any adjacent orifice during bubble formation and bubble emergence as this would lead to energy wastage.
Depending upon the manufacturing process of the staple fibre, mixed design of the said spargers like combination of steam and compressed gas sparger can be used. The critical

weeping velocity of the compressed gas stream from the said spargers is very important to design sparger and corresponding compressor and receiver capacity. Typically, Weber number is kept from 2 to 10 for effective sparging. In a preferred embodiment, the orifice of the spargers are in the range of 1mm to 4mm with centre to centre distance varying from 10 to 40 times of orifice diameter. Also, the said spargers are oriented in a staggered pattern such that this design provides maximum stress to the said fibre surface during the bubble bursting. The said spargers may be arranged on the said sparging zone (108) from a single side or from both the sides, depending on the length of the said spargers. Uniform flow of bubbles from the said spargers on the said fibre bed is one of the main objective of the present invention as this leads to uniform opening of the said fibre, avoiding fibre lump formation.
Thereafter, the said fibre-solvent slurry (101) is dispensed to stabilization zone where an adjustable plate (109) is there to maintain specific bed height. In this zone, all the opened fibres form a uniform fibre mat. The said adjustable plate (109) can move in a forward and/or backward direction in order to provide the required bed height. In a preferred embodiment, the said adjustable plate (109) can be adjusted to maintain the bed height from 100mm to 300mm, depending upon the production of the said fibre mat. In another preferred embodiment, the inclination angle of the said adjustable plate (109) is up to 14°, most preferably 10°. A moving conveyor belt (110) transports the said fibre mat (111) to the next section for further treatment like washing, bleaching and oil treatment. Preferably, the solvent stream percolates (112) through moving conveyor (110) and is recycled back into the main stream of solvent which is then further used in the same process to form the said fibre-solvent slurry (101).
According to a preferred embodiment, there is an exhaust fan (113) fixed above the said sparging zone (108) which removes the gaseous stream (118) from this section and if required, sends it to other operational unit depending on the solvent recovery. Above the said sparging zone (108) there are also fixed valves (116) to provide controlled pulsating flow and non-return

valves (117) to minimize the stratified flow condition during said pulsating flow. In a preferred embodiment, the pulsating gaseous stream (114) comprises either compressed air or nitrogen gas or steam or any inert gas Preferably, the pressure of said gas stream should be between 0.5bar(g) to 8 bar(g), depending upon the density of the stream and effect on wet fibre opening. Higher pressure leads to Taylor bubble formation that creates pockets and rolling motion in the fibre mat which results to entanglement of fibre which is undesirable in the process.
Preferably, sparger manifolds (115) are designed to provide a uniform flow of said pulsating gas stream (114), across the said sparging zone (108).
In a preferred embodiment of the present invention, a solvent stream enters the device just before the said distributor plate (106) which also has a system for back flush (119) which provides back flush to the said solvent stream and also removes stagnant lumps from said distributor plate (106).
According to another embodiment of the present invention, the said solvent may be water or N-Methyl-Morpholine N-oxide (NMMO) or ionic liquid or a mixture thereof.
In another preferred embodiment of the present invention, the said feed line (103) may be horizontal with an upward or downward inclination in order to provide uniform flow to the said fibre-solvent slurry (101). The uniformity of flow of the said fibre-solvent slurry (101) also depends upon the length and angle of inclination of the said feed line (103).
In a preferred embodiment, the gap between the said fibre feeding arm (105) and the said distributor plate (106) is between 50mm to 300mm in order to eliminate fibre choking in the said device.
In another preferred embodiment of the present invention, the orientation of the said fibre feeding arm (105) to the said distributor plate (106) is between 10° to 30° from the

horizontal axis of the base plate in order to provide a trajectory motion to the said fibre-solvent slurry (101).
The invention is defined by the claims that follow.

We claim:
1. A device for opening wet staple fibre to yield a uniformly loosened fibre mat
comprising:
a) a fibre feeding arm movable up to 45° with reference to the central axis of a trough for introducing a mixture of staple fibre and dilute solvent into the trough;
b) a distributor plate encasing the said arm defining a gap of 50mm to 300mm between the said plate and the said arm, the said arm being oriented at an angle of up to 45° from the horizontal axis of a base plate, the slope of the said distributor plate being 2° to 15° with reference to the base plate for uniform distribution of the fibre-solvent slurry across the said trough;
c) a sparging zone comprising a plurality of spargers arranged sequentially where each sparger has a plurality of orifices oriented in staggered pattern releasing a pulsating stream of compressed gas into the fibre-solvent slurry to open wet staple fibre in the said slurry stream; and
d) a fibre stabilizing zone for fibre mat formation comprising a means for obtaining a desired fibre bed height.

2. The device as claimed in claim 1, wherein a gap of 200mm to 400mm exists between the distributor plate and the sparging zone.
3. The device as claimed in claim 1, wherein an inclined falling zone exists between the distributor plate and the sparging zone.
4. The device as claimed in claim 3, wherein the inclined falling zone has a 10° to 40° slope.

5. The device as claimed in claim 1, wherein the fibre stabilizing zone comprises a movable plate having an inclination angle up to 14° and adjustable to obtain a desired bed height.
6. The device as claimed in claim 1, wherein the sparging zone has a length between 1.5m to 3 m.
7. The device as claimed in claim 1, wherein the orifices of the spargers have a diameter of 1mm to 4mm with centre to centre distance varying from 10 to 40 times of orifice diameter.
8. The device as claimed in claim 1, wherein the orifices of the spargers are positioned relative to each other such that bubbles of compressed gas emerging from any orifice do not coalesce with the bubbles emerging from any adjacent orifice during bubble formation.
9. The device as claimed in claim 1, wherein the compressed gas is air, nitrogen, steam, inert gas, or a combination thereof.
10. A method for opening wet staple fibre to yield a uniformly loosened fibre mat, the method comprising:

d) dispensing a mixture of staple fibre and dilute solvent into a trough;
e) injecting a pulsating stream of compressed gas into the slurry through the orifices of multiple spargers;
f) forming a uniformly loosened fibre mat,

wherein the orifices of the spargers are positioned relative to each other such that bubbles of compressed gas emerging from any orifice do not coalesce with the bubbles emerging from any adjacent orifice.
11. The method as claimed in claim 10, wherein the solvent is water, N-Methyl-
Morpholine N-oxide (NMMO), ionic liquid or a mixture thereof.
12. The method as claimed in claim 10, wherein the compressed gas is air, nitrogen, steam,
inert gas, or a combination thereof.