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 system for controlling moisture content in a fibre web during the staple fibre
manufacturing process.
APPLICANT:
Aditya Birla Science and Technology Company Pvt. Ltd., Plot number 1 and 1-A/1, 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
[001] The present invention relates to a system for controlling moisture content in a fibre web during the staple fibre manufacturing process. More particularly, the present invention relates to a system for controlling moisture content in a fibre web, in a timely manner, during the staple fibre manufacturing process using thermal imaging technique.
BACKGROUND OF THE INVENTION
[002] During the process of manufacturing of staple fibre, filament fibre is cut into a particular length with the help of a cutter and then it is treated further by washing, bleaching, oil-treatment to get the desired quality. Post the treatment process, wet fibre is dried before going for final packing. During the drying process, the wet fibre passes through a drying section which is divided into various zones having different temperature ranges. At the end of the drying section, dried fibre is obtained. The standard moisture percentage in the dried fibre is in the range of 10-12%.
[003] In the current practice of fibre drying, dried fibre is conveyed to a fine opener that opens the dried fibre web. This opened dried fibre is then sent to the baling press. At the bailing press, the opened fibre is pressed and compacted into rectangular bales. Post this, the fibre bales are passed through a moisture analyser to measure the moisture percentage in the dried fibre. In the event the fibre bales do not fall in the prescribed range of moisture percentage, a control action is taken at the drying section end.
[004] Moisture content is one of the quality parameters for fibre. However, presence of wet patches in the final dried fibre contributes to overall moisture variation in the final product. So, it is required to control the percentage of these wet patches within the pre-determined range. However, the process of measuring moisture percentage of the fibre bales by the moisture analyser takes around 8-10 minutes. This delay in measurement of moisture percentage causes

delay in the control action that can be taken at the drying section, if the moisture percentage is out of the prescribed range. So in the meanwhile, 2-3 more bales go out of the prescribed moisture range due to lack of in-time control action. Also, a control action after 10 minutes may lead to over/under control action and can further disturb the overall process.
[005] Previously, attempts have been made to solve this problem by using a moisture analyser having three sensors in direct contact with the dried fibre web measuring moisture at three different locations and indicating average moisture value online. However, complete width of dried fibre web cannot be covered by these sensors. As a result, moisture cannot be measured of the section of the fibre web passing through the gap between two sensors. Also, fibre mat thickness varies with production rate which affects the measurements since sensors are calibrated for particular mat thickness only. With all these limitations, the moisture analyser is not able to provide accurate data which can be used for control of moisture variation in dried fibre. Also, this system is currently used only for indication of moisture variation and not for taking any control action on the fibre drying section.
[006] Hence, a strong need exists for an alternate system for controlling moisture content in fibre web which solves some of the problems present in the prior art as mentioned above.
SUMMARY OF THE INVENTION
[007] According to an embodiment of the present invention, there is provided a system for controlling moisture content in a downstream fibre web passing through a drying section, the fibre drying section including a plurality of drying zones each of which maintained at a pre-determined temperature through a temperature controlled mechanism during operation, the system comprising a thermal image capturing device positioned adjacent to a fibre downstream end of a drying section for capturing images of a pre-determined section of the downstream fibre web emerging out of the drying section and a computer software electronically connected

to the thermal image capturing device and the temperature control mechanism, the computer software receiving the images captured to create a thermal chart identifying a first, second and third moisture specific areas in the thermal chart, wherein the computer software triggers the temperature control mechanism to vary temperature of one or more of the plurality of drying zones when the first, second and third moisture specific areas show a deviation from the standard moisture content.
BRIEF DESCRIPTION OF THE DRAWINGS
[008] Figure 1 depicts a flow chart showing the functioning of a system for controlling moisture content in a fibre web, according to an embodiment of the present invention;
[009] Figure 2 illustrates a thermal image captured by the thermal image capturing device positioned adjacent to a fibre downstream end of a drying section, according to an embodiment of the present invention;
[010] Figure 3 depicts a graph showing the detection of a first moisture specific area having high wet fibre percentage, according to an embodiment of the present invention;
[011] Figure 4 depicts a graph showing improvement in fibre quality by using the system of the present invention as illustrated in Figure 1, according to an embodiment of the present invention; and
[012] Figure 5 illustrates a flowchart showing the temperature control mechanism, according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[013] As set out in the claims, the present invention eliminates or reduces the aforementioned problems of the prior art by providing a system for controlling moisture content in a fibre web during the staple fibre manufacturing process.

[014] According to an embodiment of the present invention, as more clearly explained in Figure 1, during the fibre manufacturing process, a downstream fibre web passes through a drying section, post its treatment. The fibre drying section is divided into a plurality of zones, each of which is maintained at a pre-determined temperature range. A thermal image capturing device is positioned adjacent to a fibre downstream end of the drying section for capturing images of a pre-determined section of the downstream fibre web emerging out of the drying section. Preferably, the thermal image capturing device is an infrared (IR) camera, according to an embodiment. There is a computer software connected to the thermal image capturing device which stores the thermal images on the hard-drive of the CPU connected through the computer software. These thermal images are then processed by the computer software to form a thermal chart. In an embodiment, the thermal image capturing device is positioned anywhere in a drying section for capturing images.
[015] Thereafter, the thermal chart identifies three types of moisture specific areas in the fibre web from the data provided in the thermal chart. The first moisture specific area is identified as the area having high wet fibre percentage, second moisture specific area is identified as the area having optimized dried fibre percentage and the third moisture specific area is identified as the area having high over dried fibre percentage respectively. Preferably, the wet patches are naturally at lower temperature than the dried fibre and so that can be detectable by IR thermal imaging camera. As depicted in Figure 2, in the thermal chart, areas which have temperature lower than 32°C would fall in the first moisture specific area i.e. area having high wet fibre percentage. The areas having temperature in the range of 40°C - 43°C would be considered as areas having an optimum dried fibre percentage and areas having temperature higher than 43°C would fall in the third category i.e. areas having high over dried fibre percentage.

[016] In order to have a standard moisture percentage of 10-12%, the wet fibre percentage should be in the range of 2 to 6%, optimum dried fibre percentage should be in the range of 80 to 95% and over dried fibre percentage should be in the range of 4 to 12%. In case of deviation from the standard moisture percentage, the computer software accordingly triggers a temperature control mechanism based on the provided control action data. In the temperature control mechanism, the temperature of one or more drying zones is increased or decreased depending upon the moisture specific areas. Also, the temperature control action can be done either automatically or manually. In case of an automatic temperature control, the computer software along with signal generator generates an analog signal to the specific drying zone to vary temperature accordingly inside each drying zone.
[017] Figure 3 depicts a graph showing the detection and quantification of wet fibre percentage. It shows the wet fibre percentage and the corresponding moisture percentage chart. As soon as wet fibre percentage exceeds the set limit, immediate control action is taken & fibre moisture is maintained within quality limit. The in-time control action on the drying section temperature based on the thermal imaging data, helps to maintain the fibre moisture within limit.
[018] Therefore, the present invention reduces the lag and a timely control action is taken Preferably, the present invention leads to improvement in fibre quality as well as in the dryer operation. Also, moisture variation in the final dried fibre is reduced. Figure 4 shows the improvement in the fibre quality by using the system of the present invention as recorded at different production lines in different fibre plants.
EXAMPLES
[019] Advantages and benefits of the system for controlling of moisture content in a fibre web
according to the embodiments of the present invention would become more apparent from the

below experimental details to a person skilled in the art. [020] Experimental Data 1:
a) A conveyor dryer with two sections A and B divided into a total of 11 zones was taken. Wet fibre having (100-105) % moisture content entered the first zone, called as the ‘A1 zone’ and dry fibre having (10-12) % moisture content exited at the last zone, called as the ‘B6 zone’. Each zone was maintained at a pre-determined temperature range by circulation of hot air inside each zone.
b) An IR camera was installed at the end of B6 zone which captured thermal images of a pre-determined section of the downstream fibre web emerging out of the drying section B, at a time interval of one minute.
c) This thermal image was then processed by a computer software that was electronically connected to the IR camera and that created a thermal chart which identified three types of moisture specific areas having high wet fibre percentage, optimized dried fibre percentage and over dried fibre percentage respectively.
d) Based on the moisture percentage values, the computer software triggered a temperature controlled mechanism to vary the temperature of one or more of the drying zones depending upon the deviation from the standard moisture content in the fibre.
e) A sample of the control mechanism developed by the computer software, depending upon the deviation from the standard moisture content in the fibre, is illustrated in Figure 5.
f) A sample control logic is depicted in Table 1 showing the temperature control mechanism wherein manual/automatic control action is taken based on the trigger by the computer software.

Table 1

wet fibre (lumps) percentage over dried fibre percentage Manual Control Action
2 – 5 % 4 – 12 % No control action
5 – 7 % 4 – 12 % Increase B4 zone temperature up to 2°C
7 – 10 % < 4 % Increase B4 & B3 zone temperature separately or combined up to 5°C
> 10 % < 4 % Increase A4 /A5 zone temperature up to 7°C and B4 & B3 zone temp up to 7°C after 10 - 15 min reduces the B zone temp to initial temp.
2 – 4 % 12 –14 % Decrease B4 zone temperature up to 2 / 3°C
< 2 % > 16 % Decrease A4 /A5 zone temperature up to 5/6°C and B4 & B3 zone temp up to 5°C after 10 - 15 min increases the B zone temp to initial temp.
[021] The foregoing description of specific embodiments of the present invention has been presented for purposes of description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obvious modifications and variations are possible in light of the above teaching.
[022] The invention is defined by the claims that follow.

We claim:
1. A system for controlling moisture content in a downstream fibre web passing through a
drying section, the fibre drying section including a plurality of drying zones each of which
maintained at a pre-determined temperature through a temperature controlled mechanism
during operation, the system comprising:
- a thermal image capturing device positioned adjacent to a fibre downstream end of a drying section for capturing images of a pre-determined section of the downstream fibre web emerging out of the drying section; and
- a computer software electronically connected to the thermal image capturing device and the temperature control mechanism, the computer software receiving the images captured to create a thermal chart identifying a first, second and third moisture specific areas in the thermal chart,
wherein the computer software triggers the temperature control mechanism to vary temperature of one or more of the plurality of drying zones when the first, second and third moisture specific areas show a deviation from the standard moisture content.
2. A system for controlling moisture content in a downstream fibre web as claimed in claim 1, wherein there is more than one drying section having a plurality of drying zones, having another image capturing device positioned adjacent to its fibre downstream end and electronically connected to the computer software.
3. A system for controlling moisture content in a downstream fibre web as claimed in claim 1, wherein the thermal image capturing device is positioned anywhere in a drying section for capturing images.
4. A system for controlling moisture content in a downstream fibre web as claimed in claim 1, wherein the temperature control mechanism varies the temperature of one or more of the

plurality of drying zones by controlling the opening of a valve fitted on a pipe placed outside each drying zone to regulate the flow of steam passing through the pipe.
5. A system for controlling moisture content in a downstream fibre web as claimed in claim 1, wherein the computer software triggers the temperature control mechanism to vary temperature of one or more of the plurality of drying zones in a sequential manner starting from the drying zones at the fibre downstream end towards the drying zones at a fibre upstream end.
6. A system for controlling moisture content in a downstream fibre web as claimed in claim 1, wherein the thermal image capturing device comprises of an infra-red camera.
7. A system for controlling moisture content in a downstream fibre web as claimed in claim 1, wherein the first, second and third moisture specific areas in a thermal chart are identified as the areas having high wet fibre percentage, optimized dried fibre percentage and over dried fibre percentage respectively.
8. A system for controlling moisture content in a downstream fibre web as claimed in claims 1 and 7, wherein when the computer software creates the thermal chart identifying the wet fibre percentage to be 5-10 % and the over dried fibre percentage to be to be 1-4 %, the computer software triggers the temperature control mechanism which in turn increases the temperature of the third drying zone from the fibre downstream end by 2-5 degree Celsius.
9. A system for controlling moisture content in a downstream fibre web as claimed in claims 1 and 7, wherein when the computer software creates the thermal chart identifying the wet fibre percentage to be 1-3 % and the over dried fibre percentage to be around 12-20 %, the computer software triggers the temperature control mechanism which in turn decreases the

temperature of the third drying zone from the fibre downstream end by 2 to 5 degree Celsius.