When the fluid pressure in the system exceeds a preset value, controlled by the setting of helical spring 2, valve spool 1 is pushed to the right, compressing spring 2. A part of the fluid of the system flows through port a, annular clearance d and port b to the tank. Coiled tube 3 prevents oscillation of spool 1 upon sharp changes in the fluid pressure in the system. Spring 2 is regulated by screw 4.
$3622$SHP,Va$