Swing-type check off er the least pressure drop and offer simple automatic closure; when fluid flow stops gravity and flow reversal closes valve.
旋启式止回阀压降最小，能够完全自动关闭，即在介质流动停止、重力和介质倒流的状态下自动关闭阀门。
2
The cut-offvalvetype, the internal leakage is not allowed.
对于截断阀类来说，内漏是不允许的。
3
Off penetrable knife gate valve is a new type of fast-flow regulating valve with both ends opened and closed operation of actuators that can double increase headstock speed.