Wherein the control pressure is called pressure controlvalve to control the flow of known flow controlvalve to control flow through ﹑ called off and the directioncontrolvalve.
其中控制压力的称为压力控制阀，控制流量的称为流量控制球阀，控制通﹑断和流向的称为方向控制球阀。
2
When the controlvalve when the reverse, so that both fluid along the direction of movement of spool when closed, the flow controlvalve capacity will be increased.
当调节阀反向使用时，既流体沿着使阀芯关闭的方向流动时，调节阀的流通能力会增大。
3
The proportional directionvalve and the proportional relief valve were adopted to timely control the belt tension and its working principles were introduce.