Ring Traveller | Features of a Ring Traveller | Types of Traveller |Factors for Ring Traveller Selection

Traveller

Traveller is a tiny element which is used in ring spinning system , acts as the main of twist imparter during yarn production. On the other word , it is also called the twisting element merely responsible for twist impartion.It is a C-shaped, metal clip that revolves around the ring on a ring spinning frame. It guides the yarn onto the bobbin as twist is inserted into the yarn.

Ring Traveller

The traveller allows the twisting and the correct delivery of the yarn on the bobbin. The take up speed of the yarn, which corresponds to the difference between the peripheral speed of the bobbin and the peripheral speed of the traveller, is equal to the peripheral speed of the delivery cylinders of the drafting unit. The difference between spindle rpm and the traveler rpm, within a specific unit of time, gives the number of coils deposited on the bobbin within a specific unit of time. Therefore, with the same spindle speed, the traveller rpm increases along with the bobbin diameter while the number of coils wound on the bobbin decreases.

When the traveller rotates the high contact pressure between the ring and the traveller creates huge friction forces that generate heat; the traveller can reach temperatures exceeding 200 ÷ 300 °C since its small mass does not allow a quick transfer of the heat to the air or to the ring. For this reason, significant improvements in ring spinning can be hardly achieved with the materials currently available, since the speed of the traveller has apparently reached its maximum limit (approx. 33 ÷ 35 m/sec for steel travellers and 45 ÷ 47 m/s for nylon-glass fibre travellers). This is why the traveller used for producing a specific type of yarn must feature the most suitable shape, mass, material, finish and cross section. To reach the highest speeds, the shape of the traveller must correspond to the shape of the ring.

This creates a very large contact surface, which facilitates heat transfer; the surface must also be very smooth to grant a low barycentre. The flat profile must allow space enough for the yarn since the friction between the yarn and the ring could increase the yarn hairiness and consequently the formation of flying fibres.

The mass of the traveller determines the friction force between the ring and the traveller, the balloon size and consequently the take up tension of the yarn. If the mass of the traveller is very small, the balloon will be sufficiently large, the take up tension will be limited and the bobbin will be soft; on the contrary, a heavy traveller will determine an increase in the take up tension and a greater number of breaks. In a few words, the mass of the traveller must be strictly proportional to the yarn mass (count and resistance) and to the speed of the spindle. 

Features of a Traveller:

1. Generate less heat
2. Dissipate heat fastly
3. Have sufficient elasticity for easy insertion and to retain its original shape after insertion
4. Friction between ring and traveller should be minimal
5. It should have excellent wear resistance for longer life
6. Hardness of the traveller should be less than the ring

Types of Traveller:

Traveller are normally three types. They are:

1. OS -Type
2. C-Type
3. G-Type

Factors for Ring Traveller Selection :

1. Count of yarn to be spun
2. Fiber used in the yarn
3. Ring cup diameter
4. Spindle speed

Basic Woven Structure | Classification of Basic Woven Structures

The form of interlacing of warp and weft yarns can be divided basically into three categories- plain, twill and satin/sateen weave. These three kinds of forms are called basic weaves.

1. Plain Weave: 

The simplest of all weaves is the plain weave. Each filling yarn passes alternately over and under one warp yarn. Each warp yarn passes alternately over and under each filling yarn. Some examples of plain-weave fabric are crepe, taffeta, organdy, and muslin. The plain weave may also have variations, which include the following:

Warp rib weave- Warp rib weaves may be described as plain weave in which two or more picks are inserted in the same shed. Warp rib weaves are normally used in warp faced constructions. The warp cover factor and the warp crimp are substantially higher than the weft cover factor and the weft crimp. The intention is to produce fabrics with prominent weft-way rib formed by the crowns of the warp threads.
 

Weft rib weave- Weft rib may be described as plain weave in which two or more ends weave together as one. It is difficult to achieve very high weft cover factors in weft faced plain-weave cloths. By using two finer ends weaving as one, it becomes possible to achieve higher weft cover factor. Such cloths are expensive to weave and not very common.
 

Basket, matt or hopsack weave- In matt, basket or hopsack weaves two or more ends and two or more picks weave as one. The simplest and commonest of these weave is 2/2 matt.
(Refer to Annex 2 for weave diagrams)

2. Twill Weave: 

A weave that repeats on 3 or more ends and picks & produces diagonal lines on the face of the fabric. A twill weave is characterized by diagonal rib (twill lines) on the face of the fabric. These twill lines are produced by letting all warp ends interlace in the same way but displacing the interlacing points of each end by one pick relative to that of the previous end. In twill weave line moves sinisterly (Right - Left, Z twill) and dextrally (Left - Right, S twill). Common derivatives of twill weave are as follows:
 

Zigzag Weave- If the direction of the diagonal in a twill fabric is reversed periodically across the width, a zigzag effect is produced. Zigzag weave is achieved by simply combining two S and Z twill weaves of equal repeat.

Diamond weave- Diamond weaves are achieved by combining two symmetrical zigzag weaves of equal repeat. Diamond designs are vertically and horizontally symmetrical.
 

Herringbone weave- In Herringbone weave also the twill direction is reversed periodically like zigzag weave but at the point of reversal the order of interlacement is also reversed and then twill line commence as usual.
 

Diaper weave- Diaper weaves are produced when we combine two Herringbone designs. Diaper designs are diagonally symmetrical. (Refer to Annex 2 for weave diagrams)

3. Satin/sateen Weave: 

The satin weave is characterized by floating yarns used to produce a high luster on one side of a fabric. Warp yarns of low twist float or pass over four or more filling yarns. The low twist and the floating of the warp yarns, together with the fiber content, give a high degree of light reflection. Weights of satin fabrics range from chiffon satin to heavy duchesse satin. The sateen weave is similar to a satin construction except that in the sateen weave, the filling yarns float and are visible on the surface of fabric. Examples: cotton sateen, and damask.