Abstract
When an automatic weigh feeder is used on a worsted card, the discountinuous operation of the weigh feeder unavoidably causes periodic weight variations in the card sliver. While slivers from a number of cards are combined on the railwayballing head, the periodic weight variations in the individual card slivers are superimposed on the combined slivers and create periodic weight variations, with irregularly changing amplitudes. A slow weight variation due to a change in wool moisture also shows on the combined slivers.
The authors have designed an automatic sliver weight control device based on the open-loop control principle and used it on the railway-balling head to reduce weight variations in combined slivers. The control device has been found to eliminate periodic weight variations almost entirely, provided their wave length is more than 2 meters in terms of card slivers.