2 DE A V0432

The hydraulic counterbalance valve are modulating valves which allow free flow into the actuator and then block the reverse flow until they feel pilot pressure inversely proportional to the load in the pilot line. They employ a check valve for the free flow direction, a relief valve to control the flow in the reverse direction and a pilot piston which lowers the relief valve setting. They can lock loads in a leak free mode and they are well suited for many clamping applications or to prevent negative loads from falling down in case of hose failure. For load lowering, they improve motion control in most systems because they compel the directional control valve to always meter positive pressure, also under overrunning load conditions. Counterbalance valves can be used with paired cylinders: pilot pressure will open first the valve of the most heavily loaded cylinder; this will cause load transfer to the other cylinder and the related valve, still…