When the pressure of the fluid flowing through ports 1 exceeds the preset value, controlled by the setting of helical spring 6, fluid flowing through channel 2 pushes plunger 3 and spool 4 to the right, opening chamber 5 from which fluid drains to the tank. Narrow channel 2 operates as a damping orifice for damping the oscillations of the valve spool. When the pressure drops, spring 6, regulated by threaded member 7, pushes spool 4 to the left, closing chamber 5.
$3610$SHP,Va$