Factors to be Considered for the Selection of Correct Ring Traveller Size
Md. Abu Sayed
Pabna Textile engineering college, Pabna, Bangladesh
Email: sayed.bphs@gmail.com
What is ring and traveller? What are the different types of ring traveller and parts of traveller? Explain the factor to be considered for the selection of correct ring traveller size.
Ring traveller are the principal elements in the ring spinning process. Ring and traveler play a crucial role in the twisting process. The correct selection of ring traveller size has a predominant influence on the spinning performance. Traveler selection influences the end breakage rate. It is very important for the textile engineer or technologist to understand this and act on them to optimize the yarn production and quality.
Mainly there are two types of traveller depending on the curvature of the traveller or the traveller circle. Namely –
- Regular traveller – When the traveller circle represents an arc of a true circle and the horns are more or less straight, the traveller is known as a regular traveller.
- Elliptical or oval traveller – When the traveller circle is the shape of an ellipse, the travellers are known as the elliptic travellers (more preciously as oval traveller)
Regular travellers again may be of various shapes depending on the height of the bows above the horns and are generally classified into two –
- Large bow regular travellers.
- Small bow regular travellers.
Again, the radius of the side-circle of an elliptical traveller may be large or small and accordingly the oval traveller may be classified as –
- Large radius elliptic travellers.
- Small radius elliptic travellers.
The sectional parts of a traveller are –
- Bow – It is the curvature parts of the travellers.
- Horn – As the name implies these are the two ends of a traveller.
- Flange – The flange of a traveller is the openings between the two horns.
Factors to be considered for the selection of correct traveller size:
There is no hard and fast rule for the selection of correct ring traveller size for a particular count. Wrong selection makes vast difficulties for satisfactory spinning conditions. Life of the ring depends very much on the proper selection of traveller size.
Count of yarn, Spindle speed, ring, size, bare bobbin diameter, lift of the bobbin, thread guide traverse etc. all should be taken into consideration individually as well as collectively for correct selection of traveller size, because their factors primarily influence the dynamical functions of the traveller. Fundamentally, a spinner should exercise own judgment in selection the adequate size of the traveller keeping in mind the following principle –
1. Wt. of the traveller varies inversely as yarn number – Higher the count, lighter the yarn and lighter the traveller to cope with the high speed running of the yarn to insert higher T.P.I.
2. Wt. of the travellers varies inversely as spindle speed – Higher the spindle speed, lighter the traveller. Higher spindle speed used for higher count of yarn so the traveller is lighter also. Lighter traveller with higher spindle speed permits less wear of the ring.
3. Wt. of the traveller varies inversely as the ring dia – With the increased diameter of the ring, the weight of the traveller is lighter. To maintain the constant surface speed of the traveller on the ring, its rate of travel to be increased with a lighter traveller. Higher the ring diameter, higher the angle of pull and lighter is the traveller.
4. Wt. of the travellers varies inversely as the angle of pull – Higher the angle of pull lighter the traveller to maintain the constant winding tension on the yarn. The angle of pull depends on the diameter of the bobbin and ring. Higher the bobbin diameter lowers the winding tension, lighter the traveller and similar with ring diameter.
What are the forces acting on traveller?
The principle forces acting on the traveller may be summarized as follow –
- Retarding frictional forces against the passage of the thread at the thread guide and at the traveller.
- Atmospheric resistance against the movement of the balloon.
- Traveller weight.
- Balloon tension.
- Winding tension of the bobbin pull.
- Retarding forces or frictional drag due to friction between the traveller and the ring.
- Normal force due to the action of the ring against the traveller is centripetal force.
- Reaction of the traveller against the ring flange is the centrifugal force.
The magnitude of the forces under items 1, 2, 3 are very small compared with the rest; they are usually of the order of the 1/3000 th of the centrifugal force and may be negated.
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. Mr. Kiron is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
