| 摘要 |
<p>After emerging from the spinneret, the filaments are cooled by a flow of air in the blowing section (10) and then proceed through the chimney (12B) to the wind-up. The walls (26, 28) of the chimney converge towards the exit. A section (32) is porous e.g. less than 50 % in length and having a porosity of 20 to 40 %, to allow air to escape. With a rectangular chimney only one wall need be porous and additional controlled suction can be provided to assist the flow. Independent claims are included for the following: (1) A chimney in which the access doors have a porosity of less than 20 %, preferably 4 to 8 %; (2) A melt spinning process using such a chimney in which the boundary layer on the inner chimney walls is maintained without interruption along its whole length; (3) A melt spinning process of this kind in which some air can escape from the chimney prior to the exit.</p> |
