柔性盘簧始终使上、下阀门密封环处于受压状态，自动密封防漏。

Flexible disc springs automatically provide leak tightness by exerting pressure, which keeps the upper and lower valve sealing rings compressed at all times.

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其部分原因是涡轮螺旋桨飞机结构坚固，部分原因是“空中拖拉机”公司生产的油箱有多层橡胶密封，一旦子弹射穿油箱，橡胶层就会自动封闭住弹孔，减缓燃油的渗漏。

In part this is because of the turboprops' robust design, and in part because Air Tractor's fuel tanks have rubber membranes which close around bullet holes to slow leaks.

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自动校验：无袋或袋打开错误，无填充，无密封。袋子可再次利用，避免浪费包装材料及原料。

Automatic checking: no pouch or pouch open error, no fill, no seal. The bag can be used again, avoid wasting packing materials and raw materials.

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