[150] 2-way flow control valve

The advancing piston rod encounters a load half-way through its stroke. The flow control valve nonetheless ensures that the advance speed remains constant. From 0 to 2 seconds (shown at bottom right) the piston rod is unloaded and the pressure conditions remain constant. When the piston rod encounters the load, the pressure p_3 rises at the outlet of the flow control valve. (In order to allow the rapid control operations to be shown more clearly, the time scale now changes to 1/100ths of a second.) The flow control valve briefly raises the pressure p_2 downstream of the adjustable restrictor. Following this, the regulating restrictor moves to the left, and p_2 falls back to its original value, i.e. the pressure difference between p_1 and p_2 remains constant. The regulating operation shown is repeated a number of times, as the result of which p_3 increases to 2.5 MPa (25 bar) in several steps and the regulating restrictor opens more and more. (At the point at which 2.5 MPa (25 bar) is reached, the time scale changes back to 0.1 seconds.) The piston rod now travels under load just as fast as previously without load.