Utility Model No. 27862, Design No. 27861, Design No. 25478 Handle wheel load acceleration Cocking-structured safety relief valves to prevent accident by arbitrary operation  Automated safety relief valves for quality assurance Product safety assured by testing safety relief values instantaneous emission Vent plug cocking treated for users safety Oval stem O-ring to ensure excellent closeness under overpressure  Strengthened durability by projecting stem with special nylon