Sequence valve is basically used for controlling sequence of actuators such as motors or cylinders in a hydraulic system.Before controlling pressure has not reached to setting value, this valve is closed; once the setting is reached, the valve will open and oil flow enters the next actuator which begins to move so that the valve will work as a sequence controller. When the outlet of the valve is directly linked with tank, it may be used as an unloading valve.Sequence and check valve consists of an integral check valve and a sequence valve; when oil flow passes through the check valve, the pressure valve does not work. This valve can maintain back pressure in a hydraulic control circuit which may be used as a counter-balance valve.For the above two kinds of valve, only changing their upper and bottom covers can make up seven different models
without any internal structure change.

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