Contamination has been, and continues to be, a serious problem plaguing the cotton textile and apparel industries worldwide. But not any longer - with the introduction of Securoprop SP FPU by Truetzschler India, Ahmedabad.
Thiagarajar Mills, a leading textile conglomerate of South India, which aims to provide fault free and contamination free yarn to its customers, has already installed 5 Truetzschler's Securoprop SP-FPU for the company's various units. After observing the performance of the 1st unit of SP-FPU, which was quite impressive, the mills went in for 4 more units.
The name Thiagarajar is synonymous with quality products and sustained performance over the last seven decades. With more than 80,000 spindles, 480 rotors and 300 looms, the group produces 25,000 kg of yarn and 45,000 metres of fabric daily. OE counts of 6s to 12s and ring counts from 16s to 170s Ne are produced, which include gassed, mercerised and dyed yarns.
Under the visionary leadership of Mr T Kannan, managing director, Thiagarajar Mills and its sister concern Virudhunagar Textile Mills have a total sales of more than US$ 45 million. Their products are exported to more than 20 countries including USA, Europe, Australia and other south Asian countries and the group has so far won 15 prestigious exports awards.
This high-tech machine featuring sophisticated sensors and computational algorithms provides an increased detection efficiency of foreign matter in cotton. The latest technological advances include the detection of transparent materials, such as dreaded polypropylene contaminants.
SP-FPU is manufactured at Truetzschler India's state-of-the-art manufacturing facility at Ahmedabad. The three detection modules in SP-FPU comprise of different optical systems, each responding to different characteristic physical properties of the contaminants:
- Birefringence (PP module)
- Fluorescence (UV module) and
- Spectral absorption at visible light wavelengths (colour module).
The SP-FPU foreign matter separator can be configured according to the actual nature and extent of the specific contamination issue that a spinning mill is facing.
The cotton tufts enter the machine from the top through a rectangular duct, ensuring a uniform distribution of fibrous tufts across the entire working width of 1,200 mm. For the contaminants to be exposed, without being concealed by bulky tufts, a high degree of opening is required. Therefore, the SP-FPU should preferably be located immediately after an opener/cleaner, whereby material transport through the SP-FPU is achieved by vacuum air flow and never in a pressurised state. The maximum throughput of the unit is 1,000 kg/h.
The first inspection area consists of a glass duct segment and an illumination unit (1), which accommodates a fluorescent tube and a polarisation filter (2). On the other side of the glass duct, three ultraviolet (UV) fluorescent tubes (3) are utilised to illuminate the fibre flow. The tufts are monitored by a 3-CCD colour line scan camera (4) with a second polarisation filter (5) attached to it. A tilted mirror (6) directs the polarised transmitted light from the illumination unit (1) and the reflected light from the UV tubes (3) to the camera (4). The first inspection area serves to detect transparent and semi-transparent objects such as polypropylene as well as any fluorescent contaminants. These are called the PP and UV modules. The second inspection area features standard fluorescent tubes (7, 8) on both sides of the glass duct. Consequently, two tilted mirrors (9, 10) direct the light to two 3-CCD colour line scan cameras (11, 12), which are also mounted in the top section of the machine. Scanning the tuft flow from both sides increases detection efficiency since contaminants cannot be hidden behind solid cotton tufts.
The second inspection area identifies any contaminants that deviate from the cotton tufts in terms of colour and/or brightness. This is module number three - the colour module.
Each of the three cameras provides 2,048 effective pixels per line. Uniform detection sensitivity across the width of the machine is accomplished by using high quality lenses. At a working width of 1,200 mm, a total of 2,048 pixels per line, 10 m/s tuft velocity and a scanning frequency of 5.0 kHz, a resolution of 0.6 mm across the working width and 2.0 mm in the direction of material flow can be achieved.
As an integral component of the machine control unit, a powerful real-time computing device transforms and analyses the unprocessed camera data. The actual colour components and the brightness value of the specific material processed are established as reference values via a teach-in procedure. During normal operation, the camera signals are compared with these reference values and upon exceeding certain thresholds, which can be adjusted manually via a full-colour touch screen, objects are identified as contaminants.
Compressed air nozzles are arranged across the working width of the machine (13). Along with 48 pneumatic solenoid valves and a compressed air reservoir, everything is integrated into a single compact nozzle beam. The compressed air impulse is confined to three adjacent nozzles covering the actual horizontal position of the foreign object in the rectangular duct. The nozzles fire precisely at the very moment when a foreign object passes the nozzle beam. This is accomplished by two specially designed optical tuft velocity sensors, which are located in the first and second inspection areas, respectively. The compressed air flow is directed toward a collection container, perpendicular to the tuft flow. Its duration is only 30 minutes and compressed air consumption is therefore, minimal even at high extraction rates.
This form of selective removal also produces a minimum loss of usable lint of only 0.3 g of fibre per 100 kg/h throughput per ejection, which corresponds to a total waste amount of approximately 1.0% under practical conditions. Low loss of usable lint is an essential prerequisite for highly sensitive settings and thus the removal of very small contaminants. The foreign matter in the collection container is discharged continuously by means of a rotary air lock (14) and blown into a filtering bag (15) via an on-board fan. The cleaned flow of cotton tufts then proceeds to the next machine in the mill processing sequence.
The technicians at Thiagarajar Mills are highly satisfied with the performance of the SP-FPU and also recommend it to others.
Mr Kannan, managing director, Thiagarajar Mills, says the mills have a very cordial relationship with ATE and Truetzschler India as both have been responding to their needs very swiftly. He stated that the quality of Truetzschler machines meets world standards and their requirements. As these machines have very good workmanship and are "precision fit", they require less maintenance. As a result, he says that when the mills modernise their blow-room lines in 2011, without any doubt the obvious choice would be for ATE to supply and install Truetzschler machines. Mr Kannan added that, "ATE has been a reliable and a dependable business partner."