| 摘要 |
PROBLEM TO BE SOLVED: To carry out a continuous manufacture automatically by constituting a valvular flap by welding either one of an upper or a lower synthetic resin sheet and an intermediate synthetic resin sheet by a first heat welding means, and forming a bag body and a gas supply passage by welding a weldable sheet and the other one of the upper or lower synthetic resin sheet by a second heat welding means. SOLUTION: An upper and a lower sheet 1, 2 and an intermediate sheet 3 are intermittently transferred backward through tension rollers 5 respectively, and the intermediate sheet 3 and the lower sheet 2, lapped together, are supplied to the forward half part of a pressure-receiving platen 6, and further, a first heat welding means C is provided on the upper part of the sheets. Thus the heat-welded sheet 23 is obtained by the first heat welding means C, and a valve flap is formed by heat-sealing, and a part becoming a check valve is formed inside the valvular flap. Further, the sheet 23 and the upper sheet 1 lapped over the former are transferred to the rear half part of the pressure receiving platen 6, and a second heat welding means E is provided on the upper part of the upper sheet 1 for welding. Next, the upper and the lower sheet 1, 2 are closed by longitudinal and lateral heat-sealing. In this bag a gas supply path communicates only through a check valve. |
