LOPTEX

Invisible Contamination? Not with Loptex Optosonic

Contamination removal systems have been using optical sensors to detect contamination in raw cotton even though a substantial part cannot be detected by optical means.
Optical sensors will detect contaminations only if their colour will be different compared to the raw material.
Colourless contamination like white polypropylene or other synthetic materials cannot be detected. Since plastic will not absorb dyestuff, undyed spots will appear in finished goods which will not be accepted in today's competitive market.

The Optosonic Sorter of Loptex can be equipped with two different sensing devices:
The raw material will first be scanned by an Acoustic Sensor. Acoustic waves will penetrate fibrous material such as loose cotton tufts but will be reflected by contamination having a more compact surface structure like polyproplene and other synthetic materials.
Thereafter the raw material will be scanned by Optical Sensors detecting contamination on the basis of its shade.
Both sensor systems will monitor continuously the raw material in respect to its average density and brightness. Eventual changes in density, colour and brightness are automatically taken into account.
According to his needs, the user sets the threshold of density and brightness sensitivity which indicates the level of which the material will be distinguished as contamination.
Settings will be memorized for different yarn and raw material qualities and can easily be reactivated. Every contamination is classified according to its type and size. Statistical datas are available on a day to day basis for more than a year.
The contamination removed is collected in waste container of the Sorter. At the beginning of its operation this container will be emptied in a waste bag to permit the user to verify the performance of the system and if needed to modify the threshold value. Thereafter the waste can be deviated into the central waste collection system.
Key Features
The Loptex Sorter includes a rectangular duct through which the raw material is transported by the fan already existing at the end of the line. The raw material will first be presented to the Acoustic Sensor (1) and thereafter to the Optical Sensor (2). In case a contamination is detected it will be ejected by high speed pneumatic valves (3) into the waste container (4).
The Acoustic Sensor will emit ultrasonic waves which cannot be heard by human ears. Since such waves penetrate fibrous material, only one sensor is needed. To avoid the reflection of the waves by the opposite side of the duct on absorber box is installed.
If contamination with a compact surface structure (like plastic) is transported through the duct the ultrasonic waves will be reflected into the receiver. This receiver will thereafter trigger the ejection device.
The Optical Sensor consists of standard fluorescent light tubes and custom made photosensor arrays. In addition a very simple system can be achieved without the need of mirrors and focusing. If a contamination passes the set threshold the raw material will absorb more light and less light will be reflected to the photosensors which thereafter will trigger the ejection device.

The light output of the fluorescent tubes is electronically controlled. If it falls below limits the display will show an alarm. An alarm is also activated if photosensors fail. The light tubes as well as the photosensors can be replaced easily. The photosensors are grouped in several modules. This avoids the dependency on the good functioning of only one device such as a camera.
Since light does not penetrate cotton tufts, two sets of optical sensors are needed, one on each side of the duct.
Both sensors will trigger high speed pneumatic valves for the ejection of the contamination. These valves are arranged in one line, covering the full width of the duct. Only the valves placed directly in front of the contamination will be activated . The number will vary according to the setting of the user and depending on the size of the detected contamination. The duct opposite the values presents an opening through which the contamination is blown into the waste container.
Ideal positioning
Loptex offers different types of Sorter systems according to the production rate required and permitting the installations in various locations of the spinning preparation line.
The Sorter performs the best when positioned at the end of the opening line, after opening and cleaning. Here the fibers are opened to their maximum. The detection of foreign material will be more effective as the risk of contamination hidden in the fibers is practically non-existent. In addition, the number of fibers attached to the contamination will be lower (normally less than 0.1% of the production).

Loptex has sold more than 100 units in Pakistan

Renato Gerletti from Loptex said, "IGATEX is a good exhibition to reinforce our position and relationship with our customers. In terms of business generated, we are very happy with our agents The Textile Engineers of Pakistan. We already have more than 100Loptex units operating in Pakistan and there are few more in the pipe line.”
The Loptex single sorter on display at IGATEX 2004 attracted the attention of many spinners. On the other hand the Tandem Sorter is an ideal solution where the opening line is split up after blending, in this case two autonomous systems are integrated in one device”. Mr. Renato Gerletti, Loptex Srel, said “Loptex Sorter is quite popular in Pakistan and we are confident that more & more spinning mills will opt for Loptex Technology in future”.
Loptex also exhibited at ITM in Turkey. Mr. Stefano Cagnetta, Area Sales Manager said, “Our company offers the most efficient detection system of foreign fibers and foreign materials, which are integrated in the cotton blow room line”
It may be pointed out that Single Sorter by Loptex offers production rates of 800 kg/h. The option "Dual Style" permits to process two different qualities which enter consecutively in the system.