Abstract: A safety latch means for a filter assembly or like pressure vessel characterized by a shell member and a removable cover member. Locking means provided on the cover member is adapted to engage with locking means provided on the shell member to secure the cover member to the shell member. Proper engagement between the respective locking means is indicated by alignment of respective external brackets provided on the cover member and shell member. A peripheral locking clamp is provided for retaining the cover and shell members together, the locking clamp being capable of being attached only when the external brackets are aligned.