岛津单向阀是典型的座阀，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。

Shimadzu check valve is a typical seat valve, also known as check valve or check valve. Used to prevent reverse flow of oil flow in hydraulic system.

There are two types of check valves: straight through type and right angle type. The straight through check valve is installed on the pipeline with threaded connection. Right angle check valve has three forms: threaded connection, plate connection and flange connection.

Hydraulic control check valve is also known as locking valve or pressure maintaining valve. It is the same as the check valve to prevent the reverse flow of oil. However, when the reverse flow of oil flow is required in the hydraulic circuit, the control oil pressure can be used to open the check valve so that the oil flow can flow in both directions. The hydraulic control check valve adopts conical valve core, so it has good sealing performance.

When it is required to close the oil circuit, this valve can be used as a one-way locking of the oil circuit to keep the pressure. There are two leakage modes of hydraulic control check valve control oil: internal leakage type and external leakage type.

Internal leakage type can be used in the oil circuit without back pressure at the reverse outlet of oil flow; Otherwise, an external leakage type is required to reduce the control oil pressure.