Process and machine for making valve bags

摘要

1,016,381. Plastics valve bags. G. HANSEN. Oct. 23, 1962 [Nov. 21, 1961], No. 40176/62. Heading B8K. [Also in Division B5] A slit 14 (Fig. 3, not shown) in a flat plastics bag has a valve flap 150 welded behind it on three sides 151.