Description

They are composed by a relief valve (opening “B-A”) and  by a reverse flow check valve “A-B”. Initially the flow goes to a first line connected in parallel  to the B side, not shown here, and pressure increases  until reaching the selected relief setting; then the relief  valve opens and the second circuit is supplied out of A  port, while the actuator connected to the B side remains  pressurized. The incorporated check valve allows the  reverse motion of the actuators which happens without  specific control of the sequence, only depending from  the load/pressure conditions. Note that pressure at A needed to operate the second  actuator is additive to the relief setting, and, for this  reason, this valve is successfully employed to energize a  secondary actuator which only requires low pressure.