The Rexroth DV / the DRV-type throttle valve / unidirectional throttle 
 DV type throttle and DRV-way throttle valve is a relatively short-answer and the spirit of the adjustment actuator speed, flow control valves, shut down completely when it is cut-off valve. 
 The color scale marked on the knob is used to display the size of the flow regulator, the color triangle the greater the degree, the greater the flow. At the same time can still readjust the scale to return to the original settings to adjust the position. 
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