Abstract:

Objective At present, most spinning mills use negative pressure concentrated spinning. However, this spinning method relates to high the spinning cost due to high energy consumption. Thus a runner accumulating device was designed which does not depend on the use air pressure energy for yarn spinning. Specific experimental tasks in the research include spinning experiments by the device and yarn performance evaluation. The research is to be carried out to reduce yarn hairiness reduction, and it is envisaged that the high quality yarn production will reduce the reliance on negative pressure spinning.
Method Carded cotton roving was used as raw material to make yarns of 32.4, 24.3, and 19.4 tex. Spinning experiment included producing original yarn by traditional spinning machine and runner yarn by rotary transformation of ring spinning. These experiments were operated in spinning experiment machine DHU-X01. Two types of single yarn performance experiments were completed under the conditions of temperature about (20±2) ℃ and humidity of about (65±3)%, on hairiness testing, single yarn strength, yarn evenness, twist and 100 m weight test. The experiment required data analysis and collation to make comparison of two single yarn properties to verify the feasibility of the device.
Results The accumulating device has a good hair reduction effect on the 32.4, 24.3 and 19.4 tex cotton single yarns, with hairiness reduction effect above 4 mm. However, the strength of the runner yarn is weaker than the original yarn, and the breaking strength was decreased by approximately 1%-3%. This may be because of the lack of proper tension stretching between the front jaws and the runner jaws as the rotary wheel is driven by the front roller, causing low orientation of fibers in the yarn. When yarns were stretched by external forces, fiber utilization was reduced and yarn strength decrease, leading to slight worsening of yarn evenness. Experiment also showed that after the whiskers left the front jaws, they were not subjected to stable control immediately, causing increased CV value on yarn evenness. The twist test results show that runner device has no influence on yarn twist. 100 m weight was measured by yarn length gauge to investigate the difference in actual linear density. Compared with the experimental data, 100 m weight of runner yarn is 3% lighter than original yarn. There were two reasons for this phenomenon. On the one hand, the runner device moved the twist point forward to the place closer to the pipette and sucked air away together with some fiber. On the other hand, the device's clamping force between the two wheels was small and the wheel caused more friction on the whiskers, causing some fiber lost. Two experiments were carried out to analyze and verify the reasons. Through the data analysis, it is concluded that the friction between the runner and the fibers is the main reason for the decrease of 100 g weight. Subsequent experiments will solve this problem by increasing the clamping force of the runner.
Conclusion In summary, runner device has a noted improvement on cotton yarn hairiness reduction, and the spinning cost of the device is lower than that of the negative pressure compact spinning. Though runner yarn strength and yarn evenness are not as good as the original yarn, the deterioration of indicators is quite small within a reasonable range and it basically does not affect the use of single yarn. If the rotor wheel size is further reduced, for which the runner accumulating device is closer to the front jaw, it is expected to better results could be achieved. For producing yarns in a certain fineness range, it is promising that the low-cost runner accumulating device could replace RoCoS and negative pressure compact devices.

Key words: compact spinning, runner accumulating device, cotton yarn, hairiness test, breaking strength, yarn evenness