在使用设置在油箱管线中的偏置阀或其它流动阻塞件偏压到最小系统压力的液压系统中，在旁通管路中设置排气和充注阀，液压系统首先通过该排气和排出阀 并随后用液压流体填充。 当差压克服弹簧元件的预调节力时，阀关闭旁路。 为此，阀具有可移动安装的阀体，其具有集成的节流阀和密封面，当阀体由于压差而偏离弹簧元件的偏置力而偏离通孔时封闭通孔。

In a hydraulic system, which (PV) or other flow obstacle is biased to a minimum system pressure by one in a tank line (TL) arranged back pressure valve, an evacuating and filling valve (VFV) is in a bypass line (BL) to the back pressure valve (PV) provided by through which the hydraulic system is first evacuated and then filled with a hydraulic fluid. The valve (VFV) closes off the bypass (BL) when a pressure difference (p ₁ -p ₂₎ a preset force of a spring element, overcomes (F 4). For this purpose the valve (VFV) has a displaceably mounted valve body (3) with integrated choke (8) and a sealing surface (7), which closes a through-opening (5) when the valve body (3) due to the pressure differential against the biasing force of the spring element ( F) is displaced.