Doubling Frame || Types || Passage

Passage of Doubling frame and Types of Doubling

The usual ring doubler resembles very closely to the ringframe and the twisting and the winding mechanism are more or less similar to that of ringframe. The creel in doubling zone is modified to take cones, cheese and the thread guides are provided to guide the yarn to the delivery roller. In doubling frame only one pair of delivery roller is required because there is no drafting. The following figure shows passage of yarn through doubling frame.

Fig- Passage of Yarn through Doubling Frame

Fig- Yarn passing through Delivery roller

There are two systems of doubling namely, wet doubling system and dry doubling system. Wey doubled yarns are harder, stronger and more wiry. Due t wetting the protruding fibers get tucked in during the operations and hence these yarns are much less hairy.

To understand, the types of wet doubling system and the passage through doubler frame consider the above mention figures,

• In (a), the yarn from the creel passed over top roller goes through the nip between the top and bottom roller and is delivered after passing around the bottom roller. In this case the rollers are required to run in inward direction.
• In (b) the threading arrangement is exactly opposite to that of (a) the yarn from the creel first passes around the bottom roller then through the nip and is finally delivered after passing over the top roller.
• In (C) the yarn from the creel passes over ‘O’ guide is fed straight through the nip between top and bottom delivery rollers and then t passes around the  top roller and reversed in its direction. The yarn then curves the glass rod guide and is lead once again through the nip between the top and bottom delivery roller and then passes into the twisting zone.

The dry doubling systems mentioned in the above figure are Modifies stock port, stock port and Nottingham threading respectively.

Wet Doubling Systems:

The different types of wet doubling system English system of wet doubling, Scotch system, American system, Modified stock port and Nottingham threading.

English System of Wet doubling:

Fig-English Wet Doubling system

In English system the yarn from the creel is made to pass under glass rod immersed in water trough. The yarn is then directed to a system of a pair of delivery rollers and finally led to twisting zone. Water taps are situated at one of the ends of trough, similarly there is also a drain pipe provided at the bottom of through to run the water off, an arrangement is also provided for lifting the immersed glass rods. This facilitates easy cleaning of trough. The delivery rollers are two inches in diameter and are brass coated. The yarn after passing through the water through gets wet. The weight of the top roller effects the squeezing action on the wet yarn, this action squeeze excess of water it also helps the water to penetrate the body of the yarn.

Scotch system of doubling:

Fig-Scotch System of Doubling

 

In scotch system of system, the water trough is carried by the supports placed on the beam. A hollow brass rollers of 2 and a half inches diameter is placed in the trough, it is partially submerged. In this system the wetting action is immediately followed by the squeezing action. The yarn finally passes over the grooved glass rod; each grooved being approximately placed over corresponding spindle which carries out twisting.

Different types of Doubling Products:

• Doubled yarns may be used most commonly as warp or selvedge threads.
• Air craft fabric is an example of doubled yarn being used for both warp and weft.
• Some other typical examples are fishnets, tyre yarns, cords, twines, sewing  threads, lace yarns, ties, sacks etc.