CONDENSER SYSTEM (Derby Doubler Method)

The waste used in the spinning of cotton condenser yarns is chiefly the best class of hard waste, viz., cop bottoms, with sometimes a judicious addition of reelers' and winders' waste. The selection of material to be used in the production of condenser yams requires very careful attention and no small amount of skill and experience. Apart from colour, the guiding feature in the mixing of cop bottoms is uniformity of counts of the waste threads within certain limits. When one considers the factors employed in determining the standard amount of twist per inch in cotton yarns, viz., counts X 3.25 for weft, and counts X 3.75 for twist, it is obvious that if, say, 24's American and 80's Egyptian were mixed together the treatment necessary to tear the threads of 24's back again into fibre would not be nearly sufficient to put the 80's into the same condition. The result would be badly broken-up material, which would hamper the subsequent operations to an alarming extent. Assuming, then, that the waste purchased is of suitable quality, the first operation is to put down a mixing of the selected grades. The most satisfactory method is to spread layer after layer until the mixing is of sufficient size or weight. The attendant should then pull the waste along the whole of the face of the mixing. In this way a thorough blending takes place, with the risk of variation in shade reduced to a minimum.

Coarse yarns spun from the waste of the spinner and used as warp for cheap cotton suitings, towels, sheetings, sponge cloth, etc. Its chief characteristic is strength, so it is generally used for warp yarns. The method of spinning diners from that for condenser yarns. As with the condenser system there are two kinds of preparation spinning. The hard waste section includes cop waste, reelers', winders', doublers', ring waste, etc. The soft waste section produces yarns from comber waste, strips, blowings, fly, droppings, etc. The machinery used in the average hard waste mill comprises cop bottom breakers, scutchers, breaker cards, Derby doublers, finisher cards, roving frames, mule or ring frames. The manipulation of the material is the same as for condenser spinning up to and including the Derby doubler. The laps from the Derby doubler are fed to the finisher card in the usual way. As the web reaches the doffer it is divided into four, five, or sometimes six slivers. Each sliver is then drawn through a " trumpet" by rollers, and thence through a coiler into a can (see waste)