Sequence valves provide ordered sequencing of two or more operations as with clamp and drill circuits. They can also be used as relief valves where the down-stream pressure is high or changes during operation. By taking the drain line directly to tank, back pressure effects are negated.
As in the case of Balanced Piston Relief valves, when the inlet pressure at Pressure Port (1) exceeds the valve setting, the pilot section opens causing a flow across the orifice resulting in a small pressure drop across the piston. This subsequently moves back against a light spring opening up the PressurePort (1) to the Sequenced Port (2).
Hardened, match ground and honed working parts give long, trouble-free life. There is a consistent and stable operation providing a low pressure override even with increasing flows. Cartridge construction gives maximum flexibility in mounting.