| 摘要 |
<p>PURPOSE:To make it possible to remove foreign matters entering from the outside and fine particles developing in a bubble by a method wherein a compact gas circulating and circulating gas purifying mechanism, which is realized by arranging a fan and a filter in the bubble so as to suck the gas in the bubble with the fan in order to pass it through the filter and blow it in the bubble for circulation, is added to the inflation method. CONSTITUTION:A bubble 7 is formed by extruding resin from an annular die lip 5 and folded by guide plate 8 and wound up to a winder 10. At the same time, a fan 15 is driven in order to circulate the gas in the bubble. In this case, since molten resin has high temperature, the interior of the bubble 7 becomes germ-free condition. Further, fine particles come from molten resin at the lower part of the bubble 7 are born by the gas circulated with a fan 15 and passed through gas passages 11 so as to be separated with a filter 16. As a result, since only the gas is sent back into the bubble, the interior of the bubble 7 is kept at germand dust-free conditions. By the way, at starting, the outside air is introduced through the flow passages 11 in the bubble. After the interior of the bubble stabilizes, the fan 15 is started.</p> |
