This counterbalance valve is a 6-size metric, 3-ported, externally piloted low leakage, cartridge style valve with atmospheric vent. The check section allows free flow from the directional valve (port 2) to the load (port 3), while normally blocking flow from port 3 to port 2. Reverse flow is blocked until pilot pressure is applied at port 1. When the pressure at port 3 rises above the pressure setting, the integral relief valve is activated and vents the area behindthe pilot piston.
Atmospheric vented valves are applied when it is not practical to connect a separate vent line to the tank. Use a single counterbalance valve when the load is unidirectional, such as aerial lifts, cranes, or winches. In load holding applications, they are suitable as hose-break valves when installed near or within an actuator. Dual cartridges can be used for controlling loads bi-directionally in motor applications, or for cylinders going over center. Since this valve is piloted at port 1, no cross port drilling is required when dual cartridges are mounted nose to nose in an HIC.