单向阀又称止回阀或逆止阀。用于液压系统中防止油流反向流动。单向阀有直通式和直角式两种。直通式单向阀用螺纹连接安装在管路上。直角式单向阀有螺纹连接、板式连接和法兰连接三种形式。液控单向阀也称闭锁阀或保压阀，它与单向阀相同，用以防止油液反向流动。但在液压回路中需要油流反向流动时又可利用控制油压，打开单向阀，使油流在两个方向都可流动。液控单向阀采用锥形阀芯，因此密封性能好。在要求封闭油路时，可用此阀作为油路的单向锁紧而起保压作用。液控单向阀控制油的泄漏方式有内泄式和外泄式二种。在油流反向出口无背压的油路中可用内泄式；否则需用外泄式，以降低控制油压力。

Checkvalvesorasaone-wayvalve.Forthehydraulicsystemtopreventreverseflowofoilflow.

Astraight-throughone-wayvalvesandrectangularTypetwo.Straight-throughone-wayvalvesinstalledinaconnectingthreadofthepipeline.Rectangularstyleisaone-wayvalveconnectingthread,flangetypeconnectivityandconnectingthreeforms.Fluidcontrolvalvesalsoknownasone-waypressurevalveclosedvalvesorinsurance,withthesameone-wayvalvestopreventreverseflowofoil.However,theneedforoilflowinhydrauliccircuitreverseflowscanusehydrauliccontrol,openingaone-wayvalve,sothattheflowofoilcanflowinbothdirections.Fluidcontrolone-wayvalveusedconedisc,sealedagoodperformance.oilflowclosedindemand,theavailabilityofone-wayvalvesasoilflowparkskyPaulpressure.Fluidleakagecontrolone-wayvalvescontrolthemannerofoilandoil-leakingTypeIIspecies.NoreverseflowofoilexportsintheoilflowavailablewithininflowType;Otherwiserequiredoutflowtype,thecontrolofoilinordertoreducepressure.