特点 Features：

此类膨胀节的两端各有一个工作波纹管，中间有一个平衡波纹管，膨胀节通过受力构件（大拉杆或舌管）来承受内压推力，因此管系只需中间固定支架。此类膨胀节只能吸收轴向位移。

Each of the two ends of this type of expansion joints has a working bellow, and there is a balanced bellow in its middle, the expansion joints bear the internal pressure pushes through the stress bearing elements (large pull rod or tongue pipes), therefore the pipe system only needs the central fixing support. This type of expansion joints only absorbs axial displacement.