Automatic safety lock-out mechanism for a pressure vessel door

摘要

A safety lock-out apparatus for an access door of a pressure vessel which operates automatically without relying on external power sources is provided. The lock-out apparatus includes a locking assembly having a lock member which is supported in a hollow lock chamber for movement between a retracted position and an extended position. The lock member and a complementary recess being arranged such that when the lock member is in the extended position it engages the complementary recess so as to prevent the access door from being opened. The lock housing chamber is in fluid communication with the interior of the pressure vessel such that when the interior of the pressure vessel is pressurized, the increased pressure bears on the lock member and moves it counter to the bias of a spring into the engaged position thereby locking the door. When the increased pressure is removed from the pressure vessel, the spring moves the lock member into the retracted position.