Eaton Vickers Pressure Relief Valves

The pressure present in port P acts on the main spool (3). At the same time pressure is applied via the control lines (6) and (7), which are fitted with orifices (4) and (5), on the spring loaded side of the main spool (3) and at the ball (8) in the pilot control valve (2). If the pressure in port P exceeds the valve set at the spring (9), the ball (8) opens against the spring (9). The signal for this comes internally via the control lines (10) and (6) from port P. The pressure fluid on the spring loaded side of the main spool (3) now flows via the control line (7), orifice bore (11) and ball (8) into the spring chamber (12). In type CG2V it flows internally via the control line (13) to tank, or in type CG2V…Y externally via the control line (14). Due to the orifices (4) and (5) a pressure drop occurs at the main spool (3), the connection from port P to port T is open. Now the pressure fluid flows from port P to port T whilst maintaining the set operating pressure. The pressure relief valve may be unloaded or switched over to a different pressure (second pressure stage) via port X (15).