摘要 |
<p>An apparatus and method for uniformly irradiating a strand (22) of plastic material by twisting the strand as it is advanced in a plurality of paths transverse to an electron beam. A set of pinch rolls are positioned on opposite ends of the electron beam generator to advance and twist the strand. Lift cams (43a, 43b) periodically release the twist on the strand at positions of maximum twist by forcing the pinch rolls apart. Each set of pinch rolls includes upper (31a, 31b) and lower rolls (32a, 32b) adjacent a medial roll (30a, 30b) which, in turn, is driven in alternating axial directions to impart twist to the strand. The medial rolls are driven in alternating axial directions by a cammed surface (40b) thereon and a cam follower (41b) and synchronized to move 180° out of phase from each other. A series of three spaced apart idler rolls are also provided to form a tandem figure-eight pattern in side view for the strand to compensate for reel set in the strand.</p> |