Small-caliber totally-closed dead load type safety valve

The invention discloses a small-caliber totally-closed dead weight type safety valve, belongs to the technical field of safety valves, and aims to solve the problem that the opening and closing pressure difference of a traditional dead weight type safety valve is large. The valve comprises a valve body, a valve cover, a valve rod and a valve clack body. The valve clack body opens and closes the valve seat structure, the valve rod is in sliding fit with an upper guide sleeve at the bottom of the valve deck, an adjusting rod is arranged on the upper wall of the valve deck in a sliding mode, an adjusting seat disc is arranged at the bottom of the adjusting rod, the adjusting rod is sleeved with a reseating auxiliary spring, and the two ends of the reseating auxiliary spring abut against the valve deck and the adjusting seat disc respectively. When the valve is fully opened, the valve clack body and the valve rod slide upwards, the corrugated pipe is compressed, the first flange structure abuts against the bottom