RELIEF VALVE WITH DAMPER

PROBLEM TO BE SOLVED: To improve a damper effect by ensuring the opening speed of a valve and preventing the occurrence of a delay in liquid supply to a damper chamber at the back of a valve element during closing operation. SOLUTION: In a relief valve for liquid provided a back pressure chamber 25 at the back of a valve element 7, a damper chamber 10 is arranged at the internal part of a valve element guide 5 fixed in a valve casing 1. The damper camber 10 is partitioned into a main damper chamber 11 and an auxiliary damper chamber 12 by a partition wall 5a arranged at a valve body guide 5. An orifice 14 is arranged in a through-hole to interconnect the main and auxiliary damper chambers 11 and 12, and a check valve 13 is arranged at allow only movement of liquid for a damper from the main damper chamber 11 side to the auxiliary damper chamber 12 side. Further, a damper piston 15 to partition the back pressure chamber 25 and an auxiliary damper chamber 12 and be moved togetherwith a valve element 7 is arranged on the auxiliary damper chamber 12 side. The damper piston 15 is provided with a check valve 17 to block the movement of liquid for a damper from the auxiliary damper chamber 12 to the back pressure chamber 25 during opening operation.